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Abstract:

Disclosed herein is a wireless power transmitter for solving a problem
that a collision occurs when recognizing an initial wireless power
receiver in two-way communication of wireless power transmission. A
wireless power transmitter according to a first embodiment disclosed
herein may include a transceiver configured to transmit and/or receive a
message to and/or from a wireless power receiver; and a controller
configured to control the transceiver to transmit a message for
requesting identification information to the wireless power receiver, and
determine whether the identification information is validly received from
the wireless power receiver by the transceiver in response to the
identification information request, and control the transceiver to
transmit a message for requesting sleep mode switching to the wireless
power receiver when the identification information is validly received by
the transceiver.

Claims:

1. A wireless power transmitter, comprising: a transceiver configured to
transmit and/or receive a message to and/or from a wireless power
receiver; and a controller configured to control the transceiver to
transmit a message for requesting identification information to the
wireless power receiver, and determine whether the identification
information is validly received from the wireless power receiver by the
transceiver in response to the identification information request, and
control the transceiver to transmit a message for requesting sleep mode
switching to the wireless power receiver when the identification
information is validly received by the transceiver.

2. The wireless power transmitter of claim 1, wherein the controller
controls the transceiver to transmit a message for requesting
identification information to the wireless power receiver again when the
identification information is not validly received.

3. The wireless power transmitter of claim 1, wherein the controller is
changed to a power transmission state when a response to the
identification information request is not received any more.

4. The wireless power transmitter of claim 1, wherein the controller
registers the identification information of the wireless power receiver.

5. The wireless power transmitter of claim 1, wherein the controller
determines that the identification information is validly received when a
first message for receiving identification information from the wireless
power receiver is not collided with a second message for receiving
identification information from another wireless power receiver.

6. A wireless power transmitter, comprising: a transceiver configured to
transmit and/or receive a message to and/or from a wireless power
receiver; and a controller configured to control the transceiver to
transmit a message for requesting identification information to the
wireless power receiver, and receive a message containing identification
information from a first wireless power receiver in response to the
identification information request, and transmit a message for requesting
status information to the first wireless power receiver, wherein the
message for requesting status information comprises the identification
information of the first wireless power receiver.

7. The wireless power transmitter of claim 6, wherein the controller
controls the transceiver to receive a message containing status
information from the first wireless power receiver in response to the
identification information request from the wireless power receiver.

8. The wireless power transmitter of claim 7, wherein the controller
comprises a controller configured to control the transceiver to receive a
message containing identification information from a second wireless
power receiver in response to the identification information request, and
transmit a message for requesting status information to the second
wireless power receiver, and the message for requesting status
information comprises the identification information of the second
wireless power receiver.

9. The wireless power transmitter of claim 8, wherein the controller
controls the transceiver to receive a message containing status
information from the second wireless power receiver in response to the
identification information request from the wireless power receiver.

10. The wireless power transmitter of claim 8, wherein the first
identification information and the second identification information are
different from each other.

11. The wireless power transmitter of claim 7, wherein the message
containing status information further comprises the identification
information of the first wireless power transmitter.

12. The wireless power transmitter of claim 6, wherein the controller
registers the identification information of the wireless power receiver.

13. A wireless power transmitter, comprising: a transceiver configured
for transmitting and/or receiving a message to and/or from a wireless
power receiver; and a controller configured to control the transceiver to
transmit a message for requesting identification information to the
wireless power receiver, and determine whether the identification
information is validly received from the first and the second wireless
power receiver by the transceiver in response to the request, wherein the
identification information is received through a time slot selected by
the first and the second wireless power receiver, respectively, among a
plurality of time slots, and change the time slot assigned to at least
one of the first and the second wireless power receiver when the
identification information is not validly received from the first and
second wireless power receiver.

14. The wireless power transmitter of claim 13, wherein the controller
transmits information on the changed time slot to at least one of the
first and second wireless power receiver.

15. The wireless power transmitter of claim 13, wherein the controller
controls the transceiver to transmit a message for the identification
information to the wireless power receiver again.

16. The wireless power transmitter of claim 13, wherein the controller
registers the identification information of the first and second wireless
power receiver when the identification information is validly received
from the first and second wireless power receiver.

17. The wireless power transmitter of claim 13, wherein the message for
requesting identification information comprises the number of the
plurality of time slots.

18. The wireless power transmitter of claim 17, wherein the controller
waits for a period of time corresponding to the number of the plurality
of time slots subsequent to transmitting the message for requesting
identification information.

19. The wireless power transmitter of claim 13, wherein the controller is
immediately changed to a power transmission state when identification
information is validly received from the first and second wireless power
receiver.

20. The wireless power transmitter of claim 13, wherein the controller
changes a time slot assigned to at least one of the first and second
wireless power receiver to a vacant time slot.

Description:

RELATED APPLICATION

[0001] Pursuant to 35 U.S.C. §119(e), this application claims the
benefit of earlier filing date and right of priority to U.S. Provisional
Application No. 61/501,591, filed on Jun. 27, 2011, U.S. Provisional
Application No. 61/501,584, filed on Jun. 27, 2011 and U.S. Provisional
Application No. 61/511,431, filed on Jul. 25, 2011, the contents of which
is incorporated by reference herein in its entirety.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The embodiments disclosed in the present disclosure relates to a
wireless power transmitter and method using the same, and more
particularly, to a wireless power transmitter and method using the same
for performing two-way communication.

[0004] 2. Description of the Related Art

[0005] In recent years, the method of contactlessly supplying electrical
energy to electronic devices in a wireless manner has been used instead
of the traditional method of supplying electrical energy in a wired
manner. The electronic device receiving energy in a wireless manner may
be directly driven by the received wireless power, or a battery may be
charged by using the received wireless power, then allowing the
electronic device to be driven by the charged power.

SUMMARY OF THE INVENTION

[0006] A first embodiment disclosed herein is to solve a problem that a
collision occurs when recognizing an initial wireless power receiver in
two-way communication of wireless power transfer.

[0007] Furthermore, a second embodiment disclosed herein is to solve a
problem that a collision occurs when recognizing a single/multiple
wireless power receiver(s) in two-way communication of wireless power
transfer. Furthermore, a third embodiment disclosed herein is to solve ID
recognition and collision between wireless power receivers in wireless
power transfer using two-way communication.

[0008] In order to solve the foregoing technical task, a wireless power
transmitter according to a first embodiment disclosed herein may include
a transceiver configured to transmit and/or receive a message to and/or
from a wireless power receiver; and a controller configured to control
the transceiver to transmit a message for requesting identification
information to the wireless power receiver, and determine whether the
identification information is validly received from the wireless power
receiver by the transceiver in response to the identification information
request, and control the transceiver to transmit a message for requesting
sleep mode switching to the wireless power receiver when the
identification information is validly received by the transceiver.

[0009] According to an embodiment, the controller may control the
transceiver to transmit a message for requesting identification
information to the wireless power receiver again when the identification
information is not validly received.

[0010] Furthermore, according to an embodiment, the controller may be
changed to a power transmission state when a response to the
identification information request is not received any more.

[0011] Furthermore, according to an embodiment, the controller may
register the identification information of the wireless power receiver.

[0012] Furthermore, according to an embodiment, the controller may
determine that the identification information is validly received when a
first message for receiving identification information from the wireless
power receiver is not collided with a second message for receiving
identification information from another wireless power receiver.

[0013] On the other hand, in order to solve the another technical task, a
wireless power transmitter according to a second embodiment disclosed
herein may include a transceiver configured to transmit and/or receive a
message to and/or from a wireless power receiver; and a controller
configured to control the transceiver to transmit a message for
requesting identification information to the wireless power receiver, and
receive a message containing identification information from a first
wireless power receiver in response to the identification information
request, and transmit a message for requesting status information to the
first wireless power receiver, wherein the message for requesting status
information includes the identification information of the first wireless
power receiver.

[0014] According to an embodiment, the controller may control the
transceiver to receive a message containing status information from the
first wireless power receiver in response to the identification
information request from the wireless power receiver.

[0015] Furthermore, according to an embodiment, the controller may include
a controller configured to control the transceiver to receive a message
containing identification information from a second wireless power
receiver in response to the identification information request, and
transmit a message for requesting status information to the second
wireless power receiver, and the message for requesting status
information includes the identification information of the second
wireless power receiver.

[0016] Furthermore, according to an embodiment, the controller may control
the transceiver to receive a message containing status information from
the second wireless power receiver in response to the identification
information request from the wireless power receiver.

[0017] Furthermore, according to an embodiment, the first identification
information and the second identification may be different from each
other.

[0018] Furthermore, according to an embodiment, the message containing
status information further may include the identification information of
the first wireless power transmitter.

[0019] Furthermore, according to an embodiment, the controller may
register the identification information of the wireless power receiver.

[0020] On the other hand, in order to solve the still another technical
task, a wireless power transmitter according to a third embodiment
disclosed herein may include a transceiver configured for transmitting
and/or receiving a message to and/or from a wireless power receiver; and
a controller configured to control the transceiver to transmit a message
for requesting identification information to the wireless power receiver,
and determine whether the identification information is validly received
from the first and the second wireless power receiver by the transceiver
in response to the request, wherein the identification information is
received through a time slot selected by the first and the second
wireless power receiver, respectively, among a plurality of time slots,
and change the time slot assigned to at least one of the first and the
second wireless power receiver when the identification information is not
validly received from the first and second wireless power receiver.

[0021] According to an embodiment, the controller may transmit information
on the changed time slot to at least one of the first and second wireless
power receiver.

[0022] Furthermore, according to an embodiment, the controller may control
the transceiver to transmit a message for the identification information
to the wireless power receiver again.

[0023] Furthermore, according to an embodiment, the controller may
register the identification information of the first and second wireless
power receiver when the identification information is validly received
from the first and second wireless power receiver.

[0024] Furthermore, according to an embodiment, the message for requesting
identification information may include the number of the plurality of
time slots.

[0025] Furthermore, according to an embodiment, the controller may wait
for a period of time corresponding to the number of the plurality of time
slots subsequent to transmitting the message for requesting
identification information.

[0026] Furthermore, according to an embodiment, the controller may be
immediately changed to a power transmission state when identification
information is validly received from the first and second wireless power
receiver.

[0027] Furthermore, according to an embodiment, the controller may change
a time slot assigned to at least one of the first and second wireless
power receiver to a vacant time slot.

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings, which are included to provide a further
understanding of the invention and are incorporated in and constitute a
part of this specification, illustrate embodiments of the invention and
together with the description serve to explain the principles of the
invention.

[0029] In the drawings:

[0030] FIG. 1 is an exemplary view conceptually illustrating a wireless
power transmitter and a wireless power receiver according to the
embodiments of the present invention;

[0031] FIGS. 2A and 2B are exemplary block diagrams illustrating the
configuration of a wireless power transmitter 100 and an wireless power
receiver 200 that can be employed in the embodiments disclosed herein,
respectively;

[0032]FIG. 3 is a view illustrating a concept in which power is
transferred from a wireless power transmitter to an wireless power
receiver in a wireless manner according to an inductive coupling method;

[0033] FIGS. 4A and 4B are block diagrams illustrating part of the
wireless power transmitter 100 and wireless power receiver 200 in a
magnetic induction method that can be employed in the embodiments
disclosed herein;

[0034]FIG. 5 is a block diagram illustrating a wireless power transmitter
configured to have one or more transmission coils receiving power
according to an inductive coupling method that can be employed in the
embodiments disclosed herein;

[0035]FIG. 6 is a view illustrating a concept in which power is
transferred to an wireless power receiver from a wireless power
transmitter in a wireless manner according to an resonance coupling
method;

[0036] FIG. 7 is a block diagram illustrating part of the wireless power
transmitter 100 and wireless power receiver 200 in a resonance method
that can be employed in the embodiments disclosed herein;

[0037] FIG. 8 is a block diagram illustrating a wireless power transmitter
configured to have one or more transmission coils receiving power
according to an resonance coupling method that can be employed in the
embodiments disclosed herein;

[0038]FIG. 9 is a view illustrating the concept of transmitting and
receiving a packet between a wireless power transmitter and an electronic
device through the modulation and demodulation of a wireless power signal
in wireless power transfer according to the embodiments disclosed herein;

[0039]FIG. 10 is a view illustrating the configuration of transmitting
and receiving a power control message in wireless power transfer
according to the embodiments disclosed herein;

[0040]FIG. 11 is a view illustrating the form of a signal in the
modulation and demodulation carried out in wireless power transfer
according to the embodiments disclosed herein;

[0041]FIG. 12 is a view illustrating a packet including a power control
message used in a contactless power transfer method according to the
embodiments disclosed herein;

[0042]FIG. 13 is a view illustrating the operation phases of the wireless
power transmitter 100 and wireless power receiver 200 according to the
embodiments disclosed herein;

[0043] FIGS. 14 through 18 are views illustrating the structure of packets
including a power control message between the wireless power transmitter
100 and wireless power receiver 200;

[0044]FIG. 19 is a conceptual view illustrating a method in which a
wireless power transmitter transfers power to one or more wireless power
receivers;

[0045] FIGS. 20A through 20C are conceptual views illustrating a two-way
communication process between a wireless power transmitter 100 and one or
more wireless power receivers 200 according to an embodiment disclosed
herein;

[0046] FIGS. 21A through 21G are conceptual views illustrating a process
in which a wireless power transmitter 100 recognizes a wireless power
receiver 200 at the initial stage in wireless power transfer supporting
two-way communication;

[0047] FIG. 22 is a flow chart illustrating a process in which a wireless
power transmitter 100 recognizes a wireless power receiver 200 at the
initial stage in wireless power transfer supporting two-way
communication;

[0048]FIG. 23 is a view illustrating the phase change of a wireless power
transmitter 100 during a process in which the wireless power transmitter
100 recognizes a wireless power receiver 200 at the initial stage in
wireless power transfer supporting two-way communication;

[0049]FIG. 24 is a view illustrating an operation process between a
wireless power transmitter 100 and a wireless power receiver 200 during a
process in which the wireless power transmitter 100 recognizes a wireless
power receiver 200 at the initial stage in wireless power transfer
supporting two-way communication;

[0050] FIGS. 25A through 25D are conceptual views illustrating a process
in which a wireless power transmitter 100 and a wireless power receiver
200 perform a request and response operation on various conditions in
wireless power transfer supporting two-way communication;

[0051] FIGS. 26A through 26C are views illustrating a packet containing a
request/response message used during the two-way communication process
according to the embodiments disclosed herein;

[0052]FIG. 27 is a flow chart illustrating a process in which a wireless
power transmitter 100 transfers power to a wireless power receiver 200
through a command in wireless power transfer supporting two-way
communication;

[0053]FIG. 28 is a conceptual view illustrating the phase change of a
wireless power transmitter 100 during the power transfer process
illustrated in FIG. 27;

[0054]FIG. 29 is a schematic view for explaining a process in which a
wireless power transmitter 100 recognizes an initial approach of the
wireless power receiver 200 and supplies power during two-way
communication on single wireless power transfer;

[0055]FIG. 30 is a schematic view for explaining the process of
recognizing an wireless power receiver 200 and performing communication
when the wireless power receiver 200 approaches while a wireless power
transmitter 100 performs two-way communication with another wireless
power receiver 200 during two-way communication on single wireless power
transfer;

[0056]FIG. 31 is a view illustrating an example of a message transmitted
and received between a wireless power transmitter 100 and a wireless
power receiver performing two-way communication;

[0057]FIG. 32 is a view illustrating a procedure in which a wireless
power transmitter 100 and a wireless power receiver 200 perform two-way
communication on a signal channel;

[0058]FIG. 33A is a view illustrating a process in which a wireless power
transmitter 100 which is the host searches for a wireless power receiver
200 corresponding to the client;

[0059]FIG. 33B is a view illustrating a process in which a wireless power
receiver 200 which is the client transfers wake-up to a wireless power
transmitter 100 corresponding to the host;

[0060] FIG. 34 is a conceptual view illustrating the phase change of a
wireless power transmitter 100 in the process of the wireless power
transmitter 100 solving a collision between wireless power receivers;

[0061]FIG. 35 is a flow chart illustrating a process in which a wireless
power transmitter 100 disclosed herein solves a collision between
wireless power receivers;

[0062]FIG. 36 is a conceptual view illustrating an ID recognition and
collision resolution process of a wireless power transmitter 100
requiring a sleep mode of the wireless power receiver 200;

[0063]FIG. 37 is a conceptual view illustrating a quick ID recognition
and collision resolution process of a wireless power transmitter 100
according to an embodiment disclosed herein; and

[0064] FIGS. 38A and 38B are other conceptual views illustrating an ID
recognition and collision resolution process of a wireless power
transmitter 100 not requiring a sleep mode of the wireless power receiver
200 according to an embodiment disclosed herein.

DETAILED DESCRIPTION OF THE INVENTION

[0065] The technologies disclosed herein may be applicable to wireless
power transmission. However, the technologies disclosed herein are not
limited to this, and may be also applicable to all kinds of power
transmission systems and methods, wireless charging circuits and methods
to which the technological spirit of the technology can be applicable, in
addition to the methods and apparatuses using power transmitted in a
wireless manner.

[0066] It should be noted that technological terms used herein are merely
used to describe a specific embodiment, but not to limit the present
invention. Also, unless particularly defined otherwise, technological
terms used herein should be construed as a meaning that is generally
understood by those having ordinary skill in the art to which the
invention pertains, and should not be construed too broadly or too
narrowly. Furthermore, if technological terms used herein are wrong terms
unable to correctly express the spirit of the invention, then they should
be replaced by technological terms that are properly understood by those
skilled in the art. In addition, general terms used in this invention
should be construed based on the definition of dictionary, or the
context, and should not be construed too broadly or too narrowly.

[0067] Incidentally, unless clearly used otherwise, expressions in the
singular number include a plural meaning. In this application, the terms
"comprising" and "including" should not be construed to necessarily
include all of the elements or steps disclosed herein, and should be
construed not to include some of the elements or steps thereof, or should
be construed to further include additional elements or steps.

[0068] In addition, a suffix "module" or "unit" used for constituent
elements disclosed in the following description is merely intended for
easy description of the specification, and the suffix itself does not
give any special meaning or function.

[0069] Furthermore, the terms including an ordinal number such as first,
second, etc. can be used to describe various elements, but the elements
should not be limited by those terms. The terms are used merely for the
purpose to distinguish an element from the other element. For example, a
first element may be named to a second element, and similarly, a second
element may be named to a first element without departing from the scope
of right of the invention.

[0070] Hereinafter, preferred embodiments of the present invention will be
described in detail with reference to the accompanying drawings, and the
same or similar elements are designated with the same numeral references
regardless of the numerals in the drawings and their redundant
description will be omitted.

[0071] In describing the present invention, moreover, the detailed
description will be omitted when a specific description for publicly
known technologies to which the invention pertains is judged to obscure
the gist of the present invention. Also, it should be noted that the
accompanying drawings are merely illustrated to easily explain the spirit
of the invention, and therefore, they should not be construed to limit
the spirit of the invention by the accompanying drawings.

DEFINITION

[0072] Many-to-one communication refers to a method in which one
transmitter (TX) communicates with a plurality of receivers (RXs), and
unidirectional communication refers to a communication method in which a
receiver merely transmits a required message only to a transmitter, and
bidirectional communication refers to a communication method in which
message transfer is enabled in both directions, in other words, from a
receiver to a transmitter and from a transmitter to a receiver.

PRIOR ART AND PROBLEMS

[0073] A transmitter can transfer power to a receiver using an one-to-one
unidirectional communication method, in other words, a method of
performing one-to-one communication between one transmitter and one
receiver.

[0074] However, in case where one transmitter performs communication with
a plurality of receivers, it may be difficult to perform communication
using the prior art.

[0075] It is because a collision may occur between messages that have been
sent to the same time slot when a plurality of receivers transfer
messages to a transmitter at the same time, and an error may occur in the
transferred messages due to the collision. Such a problem may occur in
both the unidirectional and bidirectional communication schemes.

[0076] As a result, the transmitter may be unable to transfer power due to
the collision while the transmitter performs communication with a
plurality of receivers.

[0077] Conceptual View of Wireless Power Transmitter and Wireless Power
Receiver

[0078] FIG. 1 is an exemplary view conceptually illustrating a wireless
power transmitter and a wireless power receiver according to the
embodiments of the present invention.

[0079] Referring to FIG. 1, the wireless power transmitter 100 may be a
power transfer apparatus configured to transfer power required for the
wireless power receiver 200 in a wireless manner.

[0080] Furthermore, the wireless power transmitter 100 may be a wireless
charging apparatus configured to charge a battery of the wireless power
receiver 200 by transferring power in a wireless manner.

[0081] Additionally, the wireless power transmitter 100 may be implemented
with various forms of apparatuses transferring power to the wireless
power receiver 200 requiring power in a contactless state.

[0082] The wireless power receiver 200 is a device that is operable by
receiving power from the wireless power transmitter 100 in a wireless
manner. Furthermore, the wireless power receiver 200 may charge a battery
using the received wireless power.

[0083] On the other hand, a wireless power receiver for receiving power in
a wireless manner as described herein should be construed broadly to
include a portable phone, a cellular phone, a smart phone, a personal
digital assistant (PDA), a portable multimedia player (PMP), a tablet, a
multimedia device, or the like, in addition to an input/output device
such as a keyboard, a mouse, an audio-visual auxiliary device, and the
like.

[0084] The wireless power receiver 200, as described later, may be a
mobile communication terminal, (for example, a portable phone, a cellular
phone, and a tablet or multimedia device).

[0085] On the other hand, the wireless power transmitter 100 may transfer
power in a wireless manner without mutual contact to the wireless power
receiver 200 using one or more wireless power transfer methods. In other
words, the wireless power transmitter 100 may transfer power using at
least one of an inductive coupling method based on magnetic induction
phenomenon by the wireless power signal and a magnetic resonance coupling
method based on electromagnetic resonance phenomenon by a wireless power
signal at a specific frequency.

[0086] Wireless power transmission in the inductive coupling method is a
technology transmitting power in a wireless manner using a primary coil
and a secondary coil, and refers to the transmission of power by inducing
a current from a coil to another coil through a changing magnetic field
by magnetic induction phenomenon.

[0087] Wireless power transmission in the magnetic resonance coupling
method refers to a technology in which the wireless power receiver 200
generates resonance by a wireless power signal transmitted from the
wireless power transmitter 100 to transfer power from the wireless power
transmitter 100 to the wireless power receiver 200 by the resonance
phenomenon.

[0088] Hereinafter, the wireless power transmitter 100 and wireless power
receiver 200 according to the embodiments disclosed herein will be
described in detail. In assigning reference numerals to the constituent
elements in each of the following drawings, the same reference numerals
will be used for the same constituent elements even though they are shown
in a different drawing.

[0089] FIGS. 2A and 2B are exemplary block diagrams illustrating the
configuration of a wireless power transmitter 100 and a wireless power
receiver 200 that can be employed in the embodiments disclosed herein.

[0090] Wireless Power Transmitter

[0091] Referring to FIG. 2A, the wireless power transmitter 100 may
include a power transmission unit 110. The power transmission unit 110
may include a power conversion unit 111 and a power transmission control
unit 112.

[0092] The power conversion unit 111 transfers power supplied from the
transmission side power supply unit 190 to the wireless power receiver
200 by converting it into a wireless power signal. The wireless power
signal transferred by the power conversion unit 111 is generated in the
form of a magnetic field or electro-magnetic field having an oscillation
characteristic. For this purpose, the power conversion unit 111 may be
configured to include a coil for generating the wireless power signal.

[0093] The power conversion unit 111 may include a constituent element for
generating a different type of wireless power signal according to each
power transfer method. For example, the power conversion unit 111 may
include a primary coil for forming a changing magnetic field to induce a
current to a secondary coil of the wireless power receiver 200.
Furthermore, the power conversion unit 111 may include a coil (or
antenna) for forming a magnetic field having a specific resonance
frequency to generate a resonance frequency in the wireless power
receiver 200 according to the resonance coupling method.

[0094] Furthermore, the power conversion unit 111 may transfer power using
at least one of the foregoing inductive coupling method and the resonance
coupling method.

[0095] Among the constituent elements included in the power conversion
unit 111, those for the inductive coupling method will be described later
with reference to FIGS. 4 and 5, and those for the resonance coupling
method will be described with reference to FIGS. 7 and 8.

[0096] On the other hand, the power conversion unit 111 may further
include a circuit for controlling the characteristics of a used
frequency, an applied voltage, an applied current or the like to form the
wireless power signal.

[0097] The power transmission control unit 112 controls each of the
constituent elements included in the power transmission unit 110 The
power transmission control unit 112 may be implemented to be integrated
into another control unit (not shown) for controlling the wireless power
transmitter 100.

[0098] On the other hand, an region to which the wireless power signal can
be approached may be divided into two types. First, active area denotes a
region through which a wireless power signal transferring power to the
wireless power receiver 200 is passed. Next, semi-active area denotes an
interest region in which the wireless power transmitter 100 can detect
the existence of the wireless power receiver 200. Here, the power
transmission control unit 112 may detect whether the wireless power
receiver 200 is placed in the active area or detection area or removed
from the area. Specifically, the power transmission control unit 112 may
detect whether or not the wireless power receiver 200 is placed in the
active area or detection area using a wireless power signal formed from
the power conversion unit 111 or a sensor separately provided therein.
For instance, the power transmission control unit 112 may detect the
presence of the wireless power receiver 200 by monitoring whether or not
the characteristic of power for forming the wireless power signal is
changed by the wireless power signal, which is affected by the wireless
power receiver 200 existing in the detection area. However, the active
area and detection area may vary according to the wireless power transfer
method such as an inductive coupling method, a resonance coupling method,
and the like.

[0099] The power transmission control unit 112 may perform the process of
identifying the wireless power receiver 200 or determine whether to start
wireless power transmission according to a result of detecting the
existence of the wireless power receiver 200.

[0100] Furthermore, the power transmission control unit 112 may determine
at least one characteristic of a frequency, a voltage, and a current of
the power conversion unit 111 for forming the wireless power signal. The
determination of the characteristic may be carried out by a condition at
the side of the wireless power transmitter 100 or a condition at the side
of the wireless power receiver 200.

[0101] The power transmission control unit 112 may receive a power control
message from the wireless power receiver 200. The power transmission
control unit 112 may determine at least one characteristic of a
frequency, a voltage and a current of the power conversion unit 111 based
on the received power control message, and additionally perform other
control operations based on the power control message.

[0102] For example, the power transmission control unit 112 may determine
at least one characteristic of a frequency, a voltage and a current used
to form the wireless power signal according to the power control message
including at least one of rectified power amount information, charging
state information and identification information in the wireless power
receiver 200.

[0103] Furthermore, as another control operation using the power control
message, the wireless power transmitter 100 may perform a typical control
operation associated with wireless power transmission based on the power
control message. For example, the signal detector 10 may receive
information associated with the wireless power receiver 200 to be
auditorily or visually outputted through the power control message, or
receive information required for authentication between devices.

[0104] In order to receive the foregoing power control message, the power
transmission control unit 112 may use at least one of a method for
receiving it through the wireless power signal and a method for receiving
other user data.

[0105] In order to receive the power control message, the wireless power
transmitter 100 may further include a power communications
modulation/demodulation unit 113 electrically connected to the power
conversion unit 111. The power communications modulation/demodulation
unit 113 may modulate a wireless power signal that has been modulated by
the wireless power receiver 200 and use it to receive the power control
message.

[0106] In addition, the power transmission control unit 112 may acquire a
power control message by receiving user data including a power control
message by a communication means (not shown) included in the wireless
power transmitter 100.

[0107] [In Case of Supporting in-Band Two-Way Communication]

[0108] Furthermore, in a wireless power transmission environment capable
of two-way communication according to the embodiments disclosed herein,
the power transmission control unit 112 may transmit data to the wireless
power receiver 200. The data transmitted by the power transmission
control unit 112 may request the wireless power receiver 200 to send a
power control message.

[0109] Wireless Power Receiver

[0110] Referring to FIG. 2B, the wireless power receiver 200 may include a
power supply unit 290. The power supply unit 290 supplies power required
for the operation of the wireless power receiver 200. The power supply
unit 290 may include a power receiving unit 291 and a power receiving
control unit 292.

[0111] The power receiving unit 291 receives power transferred from the
wireless power transmitter 100 in a wireless manner.

[0112] The power receiving unit 291 may include constituent elements
required to receive the wireless power signal according to a wireless
power transfer method. Furthermore, the power receiving unit 291 may
receive power according to at least one wireless power transfer method,
and in this case, the power receiving unit 291 may include constituent
elements required for each method.

[0113] First, the power receiving unit 291 may include a coil for
receiving a wireless power signal transferred in the form of a magnetic
field or electromagnetic field having a vibration characteristic.

[0114] For instance, as a constituent element according to the inductive
coupling method, the power receiving unit 291 may include a secondary
coil to which a current is induced by a changing magnetic field.
Furthermore, the power receiving unit 291, as a constituent element
according to the resonance coupling method, may include a coil and a
resonant circuit in which resonance phenomenon is generated by a magnetic
field having a specific resonance frequency.

[0115] However, when the power receiving unit 291 receives power according
to at least one wireless power transfer method, the power receiving unit
291 may be implemented to receive power by using a coil, or implemented
to receive power by using a coil formed differently according to each
power transfer method.

[0116] Among the constituent elements included in the power receiving unit
291, those for the inductive coupling method will be described later with
reference to FIG. 4, and those for the resonance coupling method with
reference to FIG. 7.

[0117] On the other hand, the power receiving unit 291 may further include
a rectifier and a regulator to convert the wireless power signal into a
direct current. Furthermore, the power receiving unit 291 may further
include a circuit for protecting an overvoltage or overcurrent from being
generated by the received power signal.

[0118] The power receiving control unit 292 may control each constituent
element included in the power supply unit 290.

[0119] Specifically, the power receiving control unit 292 may transfer a
power control message to the wireless power transmitter 100. The power
control message may instruct the wireless power transmitter 100 to
initiate or terminate a transfer of the wireless power signal.
Furthermore, the power control message may instruct the wireless power
transmitter 100 to control a characteristic of the wireless power signal.

[0120] In order to transmit the foregoing power control message, the power
receiving control unit 292 may use at least one of a method for
transmitting it through the wireless power signal and a method for
transmitting other user data.

[0121] In order to transmit the power control message, the wireless power
receiver 200 may further include a power communications
modulation/demodulation unit 293 electrically connected to the power
receiving unit 291. The power communications modulation/demodulation unit
293, similarly to the case of the wireless power transmitter 100, may be
used to transmit the power control message through the wireless power
signal. The power communications modulation/demodulation unit 293 may be
used as a means for controlling a current and/or voltage flowing through
the power conversion unit 111 of the wireless power transmitter 100.
Hereinafter, a method for allowing the power communications
modulation/demodulation unit 113 or 293 at the side of the wireless power
transmitter 100 and at the side of the wireless power receiver 200,
respectively, to be used to transmit and receive a power control message
through a wireless power signal will be described.

[0122] A wireless power signal formed by the power conversion unit 111 is
received by the power receiving unit 291. At this time, the power
receiving control unit 292 controls the power communications
modulation/demodulation unit 293 at the side of the wireless power
receiver 200 to modulate the wireless power signal. For instance, the
power receiving control unit 292 may perform a modulation process such
that a power amount received from the wireless power signal is varied by
changing a reactance of the power communications modulation/demodulation
unit 293 connected to the power receiving unit 291. The change of a power
amount received from the wireless power signal results in the change of a
current and/or voltage of the power conversion unit 111 for forming the
wireless power signal. At this time, the power communications
modulation/demodulation unit 113 at the side of the wireless power
transmitter 100 may detect a change of the current and/or voltage to
perform a demodulation process.

[0123] In other words, the power receiving control unit 292 may generate a
packet including a power control message intended to be transferred to
the wireless power transmitter 100 and modulate the wireless power signal
to allow the packet to be included therein, and the power transmission
control unit 112 may decode the packet based on a result of performing
the demodulation process of the power communications
modulation/demodulation unit 113 to acquire the power control message
included in the packet.

[0124] In addition, in some embodiments, the power receiving control unit
292 may transmit a power control message to the wireless power
transmitter 100 by transmitting user data including the power control
message by a communication means (not shown) included in the wireless
power receiver 200.

[0125] [In Case of Supporting in-Band Two-Way Communication]

[0126] Furthermore, in a wireless power transmission environment capable
of two-way communication according to the embodiments disclosed herein,
the power receiving control unit 292 may transmit user data containing a
power control message by a communication means (not shown), thereby
transmitting the power control message to the wireless power transmitter
100.

[0127] In addition, the power supply unit 290 may further include a
charger 298 and a battery 299.

[0128] The wireless power receiver 200 receiving power for operation from
the power supply unit 290 may be operated by power transferred from the
wireless power transmitter 100, or operated by charging the battery 299
using the transferred power and then receiving the charged power. At this
time, the power receiving control unit 292 may control the charger 298 to
perform charging using the transferred power.

[0129] Hereinafter, a wireless power transmitter and a wireless power
receiver applicable to the embodiments disclosed herein will be
described. First, a method of allowing the wireless power transmitter to
transfer power to the wireless power receiver according to the inductive
coupling method will be described with reference to FIGS. 3 through 5.

[0130] Inductive Coupling Method

[0131]FIG. 3 is a view illustrating a concept in which power is
transferred from a wireless power transmitter to a wireless power
receiver in a wireless manner according to an inductive coupling method.

[0132] When the power of the wireless power transmitter 100 is transferred
in an inductive coupling method, if the strength of a current flowing
through a primary coil within the power transmission unit 110 is changed,
then a magnetic field passing through the primary coil will be changed by
the current. The changed magnetic field generates an induced
electromotive force at a secondary coil in the wireless power receiver
200.

[0133] According to the foregoing method, the power conversion unit 111 of
the wireless power transmitter 100 may include a transmitting (Tx) coil
1111a being operated as a primary coil in magnetic induction.
Furthermore, the power receiving unit 291 of the wireless power receiver
200 may include a receiving (Rx) coil 2911a being operated as a secondary
coil in magnetic induction.

[0134] First, the wireless power transmitter 100 and wireless power
receiver 200 are disposed in such a manner that the transmitting coil
1111a at the side of the wireless power transmitter 100 and the receiving
coil at the side of the wireless power receiver 200 are located adjacent
to each other. Then, if the power transmission control unit 112 controls
a current of the transmitting coil 1111a to be changed, then the power
receiving unit 291 controls power to be supplied to the wireless power
receiver 200 using an electromotive force induced to the receiving coil
2911a.

[0135] The efficiency of wireless power transmission by the inductive
coupling method may be little affected by a frequency characteristic, but
affected by an alignment and distance between the wireless power
transmitter 100 and the wireless power receiver 200 including each coil.

[0136] On the other hand, in order to perform wireless power transmission
in the inductive coupling method, the wireless power transmitter 100 may
be configured to include an interface surface (not shown) in the form of
a flat surface. One or more wireless power receivers may be placed at an
upper portion of the interface surface, and the transmitting coil 1111a
may be mounted at a lower portion of the interface surface. In this case,
a vertical spacing is formed in a small-scale between the transmitting
coil 1111a mounted at a lower portion of the interface surface and the
receiving coil 2911a of the wireless power receiver 200 placed at an
upper portion of the interface surface, and thus a distance between the
coils becomes sufficiently small to efficiently implement wireless power
transmission by the inductive coupling method.

[0137] Furthermore, an alignment indicator (not shown) indicating a
location where the wireless power receiver 200 is to be placed at an
upper portion of the interface surface. The alignment indicator indicates
a location of the wireless power receiver 200 where an alignment between
the transmitting coil 1111a mounted at a lower portion of the interface
surface and the receiving coil 2911a can be suitably implemented. The
alignment indicator may be simple marks, or may be formed in the form of
a protrusion structure for guiding the location of the wireless power
receiver 200. Otherwise, the alignment indicator may be formed in the
form of a magnetic body such as a magnet mounted at a lower portion of
the interface surface, thereby guiding the coils to be suitably arranged
by mutual magnetism to a magnetic body having an opposite polarity
mounted within the wireless power receiver 200.

[0138] On the other hand, the wireless power transmitter 100 may be formed
to include one or more transmitting coils. The wireless power transmitter
100 may selectively use some of coils suitably arranged with the
receiving coil 2911a of the wireless power receiver 200 among the one or
more transmitting coils to enhance the power transmission efficiency. The
wireless power transmitter 100 including the one or more transmitting
coils will be described later with reference to FIG. 5.

[0139] Hereinafter, a configuration of the wireless power transmitter and
wireless power receiver using an inductive coupling method applicable to
the embodiments disclosed herein will be described in detail.

[0140] Wireless Power Transmitter and Wireless Power Receiver in Inductive
Coupling Method

[0141] FIGS. 4A and 4B are block diagrams illustrating part of the
wireless power transmitter 100 and wireless power receiver 200 in a
magnetic induction method that can be employed in the embodiments
disclosed herein. A configuration of the power transmission unit 110
included in the wireless power transmitter 100 will be described with
reference to FIG. 4A, and a configuration of the power supply unit 290
included in the wireless power receiver 200 will be described with
reference to FIG. 4B.

[0142] Referring to FIG. 4A, the power conversion unit 111 of the wireless
power transmitter 100 may include a transmitting (Tx) coil 1111a and an
inverter 1112.

[0143] The transmitting coil 1111a may form a magnetic field corresponding
to the wireless power signal according to a change of current as
described above. The transmitting coil 1111a may be implemented with a
planar spiral type or cylindrical solenoid type.

[0144] The inverter 1112 transforms a DC input obtained from the power
supply unit 190 into an AC waveform. The AC current transformed by the
inverter 1112 drives a resonant circuit including the transmitting coil
1111a and a capacitor (not shown) to form a magnetic field in the
transmitting coil 1111a.

[0145] In addition, the power conversion unit 111 may further include a
positioning unit 1114.

[0146] The positioning unit 1114 may move or rotate the transmitting coil
1111a to enhance the effectiveness of wireless power transmission using
the inductive coupling method. As described above, it is because an
alignment and distance between the wireless power transmitter 100 and the
wireless power receiver 200 including a primary coil and a secondary coil
may affect power transfer using the inductive coupling method. In
particular, the positioning unit 1114 may be used when the wireless power
receiver 200 does not exist within an active area of the wireless power
transmitter 100.

[0147] Accordingly, the positioning unit 1114 may include a drive unit
(not shown) for moving the transmitting coil 1111a such that a
center-to-center distance of the transmitting coil 1111a of the wireless
power transmitter 100 and the receiving coil 2911a of the wireless power
receiver 200 is within a predetermined range, or rotating the
transmitting coil 1111a such that the centers of the transmitting coil
1111a and the receiving coil 2911a are overlapped with each other.

[0148] For this purpose, the wireless power transmitter 100 may further
include a detection unit (not shown) made of a sensor for detecting the
location of the wireless power receiver 200, and the power transmission
control unit 112 may control the positioning unit 1114 based on the
location information of the wireless power receiver 200 received from the
location detection sensor.

[0149] Furthermore, to this end, the power transmission control unit 112
may receive control information on an alignment or distance to the
wireless power receiver 200 through the power communications
modulation/demodulation unit 113, and control the positioning unit 1114
based on the received control information on the alignment or distance.

[0150] If the power conversion unit 111 is configured to include a
plurality of transmitting coils, then the positioning unit 1114 may
determine which one of the plurality of transmitting coils is to be used
for power transfer. The configuration of the wireless power transmitter
100 including the plurality of transmitting coils will be described later
with reference to FIG. 5.

[0151] On the other hand, the power conversion unit 111 may further
include a power sensing unit 1115. The power sensing unit 1115 at the
side of the wireless power transmitter 100 monitors a current or voltage
flowing into the transmitting coil 1111a. The power sensing unit 1115 is
provided to check whether or not the wireless power transmitter 100 is
normally operated, and thus the power sensing unit 1115 may detect a
voltage or current of the power supplied from the outside, and check
whether the detected voltage or current exceeds a threshold value. The
power sensing unit 1115 may include a resistor for detecting a voltage or
current of the power supplied from the outside and a comparator for
comparing a voltage value or current value of the detected power with a
threshold value to output the comparison result. Based on the check
result of the power sensing unit 1115, the power transmission control
unit 112 may control a switching unit (not shown) to cut off power
applied to the transmitting coil 1111a.

[0152] Referring to FIG. 4B, the power supply unit 290 of the wireless
power receiver 200 may include a receiving (Rx) coil 2911a and a
rectifier circuit 2913.

[0153] A current is induced into the receiving coil 2911a by a change of
the magnetic field formed in the transmitting coil 1111a. The
implementation type of the receiving coil 2911a may be a planar spiral
type or cylindrical solenoid type similarly to the transmitting coil
1111a.

[0154] Furthermore, series and parallel capacitors may be configured to be
connected to the receiving coil 2911a to enhance the effectiveness of
wireless power reception or perform resonant detection.

[0155] The receiving coil 2911a may be in the form of a single coil or a
plurality of coils.

[0156] The rectifier circuit 2913 performs a full-wave rectification to a
current to convert alternating current into direct current. The rectifier
circuit 2913, for instance, may be implemented with a full-bridge
rectifier circuit made of four diodes or a circuit using active
components.

[0157] In addition, the rectifier circuit 2913 may further include a
regulator circuit for converting a rectified current into a more flat and
stable direct current. Furthermore, the output power of the rectifier
circuit 2913 is supplied to each constituent element of the power supply
unit 290. Furthermore, the rectifier circuit 2913 may further include a
DC-DC converter for converting output DC power into a suitable voltage to
adjust it to the power required for each constituent element (for
instance, a circuit such as a charger 298).

[0158] The power communications modulation/demodulation unit 293 may be
connected to the power receiving unit 291, and may be configured with a
resistive element in which resistance varies with respect to direct
current, and may be configured with a capacitive element in which
reactance varies with respect to alternating current. The power receiving
control unit 292 may change the resistance or reactance of the power
communications modulation/demodulation unit 293 to modulate a wireless
power signal received to the power receiving unit 291.

[0159] On the other hand, the power supply unit 290 may further include a
power sensing unit 2914. The power sensing unit 2914 at the side of the
wireless power receiver 200 monitors a voltage and/or current of the
power rectified by the rectifier circuit 2913, and if the voltage and/or
current of the rectified power exceeds a threshold value as a result of
monitoring, then the power receiving control unit 292 transmits a power
control message to the wireless power transmitter 100 to transfer
suitable power.

[0160] Wireless Power Transmitter Configured to Include One or More
Transmitting Coils

[0161]FIG. 5 is a block diagram illustrating a wireless power transmitter
configured to have one or more transmission coils receiving power
according to an inductive coupling method that can be employed in the
embodiments disclosed herein.

[0162] Referring to FIG. 5, the power conversion unit 111 of the wireless
power transmitter 100 according to the embodiments disclosed herein may
include one or more transmitting coils 1111a-1 to 1111a-n. The one or
more transmitting coils 1111a-1 to 1111a-n may be an array of partly
overlapping primary coils. An active area may be determined by some of
the one or more transmitting coils.

[0163] The one or more transmitting coils 1111a-1 to 1111a-n may be
mounted at a lower portion of the interface surface. Furthermore, the
power conversion unit 111 may further include a multiplexer 1113 for
establishing and releasing the connection of some of the one or more
transmitting coils 1111a-1 to 1111a-n.

[0164] Upon detecting the location of the wireless power receiver 200
placed at an upper portion of the interface surface, the power
transmission control unit 112 may take the detected location of the
wireless power receiver 200 into consideration to control the multiplexer
1113, thereby allowing coils that can be placed in an inductive coupling
relation to the receiving coil 2911a of the wireless power receiver 200
among the one or more transmitting coils 1111a-1 to 1111a-n to be
connected to one another.

[0165] For this purpose, the power transmission control unit 112 may
acquire the location information of the wireless power receiver 200. For
example, the power transmission control unit 112 may acquire the location
of the wireless power receiver 200 on the interface surface by the
location detection unit (not shown) provided in the wireless power
transmitter 100. For another example, the power transmission control unit
112 may receive a power control message indicating a strength of the
wireless power signal from an object on the interface surface or a power
control message indicating the identification information of the object
using the one or more transmitting coils 1111a-1 to 1111a-n,
respectively, and determines whether it is located adjacent to which one
of the one or more transmitting coils based on the received result,
thereby acquiring the location information of the wireless power receiver
200.

[0166] On the other hand, the active area as part of the interface surface
may denote a portion through which a magnetic field with a high
efficiency can pass when the wireless power transmitter 100 transfers
power to the wireless power receiver 200 in a wireless manner. At this
time, a single transmitting coil or one or a combination of more
transmitting coils forming a magnetic field passing through the active
area may be designated as a primary cell. Accordingly, the power
transmission control unit 112 may determine an active area based on the
detected location of the wireless power receiver 200, and establish the
connection of a primary cell corresponding to the active area to control
the multiplexer 1113, thereby allowing the receiving coil 2911a of the
wireless power receiver 200 and the coils belonging to the primary cell
to be placed in an inductive coupling relation.

[0167] Furthermore, the power conversion unit 111 may further include an
impedance matching unit (not shown) for controlling an impedance to form
a resonant circuit with the coils connected thereto.

[0168] Hereinafter, a method for allowing a wireless power transmitter to
transfer power according to a resonance coupling method will be disclosed
with reference to FIGS. 6 through 8.

[0169] Resonance Coupling Method

[0170]FIG. 6 is a view illustrating a concept in which power is
transferred to a wireless power receiver from a wireless power
transmitter in a wireless manner according to an resonance coupling
method.

[0171] First, resonance will be described in brief as follows. Resonance
refers to a phenomenon in which an amplitude of vibration is remarkably
increased when periodically receiving an external force having the same
frequency as the natural frequency of a vibration system. Resonance is a
phenomenon occurring at all kinds of vibrations such as mechanical
vibration, electric vibration, and the like. Generally, when exerting a
vibratory force to a vibration system from the outside, if the natural
frequency thereof is the same as a frequency of the externally applied
force, then the vibration becomes strong, thus increasing the width.

[0172] With the same principle, when a plurality of vibrating bodies
separated from one another within a predetermined distance vibrate at the
same frequency, the plurality of vibrating bodies resonate with one
another, and in this case, resulting in a reduced resistance between the
plurality of vibrating bodies. In an electrical circuit, a resonant
circuit can be made by using an inductor and a capacitor.

[0173] When the wireless power transmitter 100 transfers power according
to the inductive coupling method, a magnetic field having a specific
vibration frequency is formed by alternating current power in the power
transmission unit 110. If a resonance phenomenon occurs in the wireless
power receiver 200 by the formed magnetic field, then power is generated
by the resonance phenomenon in the wireless power receiver 200.

[0174] The resonance frequency may be determined by the following formula
in Equation 1.

f = 1 2 π LC [ Equation 1 ] ##EQU00001##

[0175] Here, the resonance frequency (f) is determined by an inductance
(L) and a capacitance (C) in a circuit. In a circuit forming a magnetic
field using a coil, the inductance can be determined by a number of turns
of the coil, and the like, and the capacitance can be determined by a gap
between the coils, an area, and the like. In addition to the coil, a
capacitive resonant circuit may be configured to be connected thereto to
determine the resonance frequency.

[0176] Referring to FIG. 6, when power is transmitted in a wireless manner
according to the resonance coupling method, the power conversion unit 111
of the wireless power transmitter 100 may include a transmitting (Tx)
coil 1111b in which a magnetic field is formed and a resonant circuit
1116 connected to the transmitting coil 1111b to determine a specific
vibration frequency. The resonant circuit 1116 may be implemented by
using a capacitive circuit (capacitors), and the specific vibration
frequency may be determined based on an inductance of the transmitting
coil 1111b and a capacitance of the resonant circuit 1116.

[0177] The configuration of a circuit element of the resonant circuit 1116
may be implemented in various forms such that the power conversion unit
111 forms a magnetic field, and is not limited to a form of being
connected in parallel to the transmitting coil 1111b as illustrated in
FIG. 6.

[0178] Furthermore, the power receiving unit 291 of the wireless power
receiver 200 may include a resonant circuit 2912 and a receiving (Rx)
coil 2911b to generate a resonance phenomenon by a magnetic field formed
in the wireless power transmitter 100. In other words, the resonant
circuit 2912 may be also implemented by using a capacitive circuit, and
the resonant circuit 2912 is configured such that a resonance frequency
determined based on an inductance of the receiving coil 2911b and a
capacitance of the resonant circuit 2912 has the same frequency as a
resonance frequency of the formed magnetic field.

[0179] The configuration of a circuit element of the resonant circuit 2912
may be implemented in various forms such that the power receiving unit
291 generates resonance by a magnetic field, and is not limited to a form
of being connected in series to the receiving coil 2911b as illustrated
in FIG. 6.

[0180] The specific vibration frequency in the wireless power transmitter
100 may have LTX, CTX, and may be acquired by using the Equation 1. Here,
the wireless power receiver 200 generates resonance when a result of
substituting the LRX and CRX of the wireless power receiver 200 to the
Equation 1 is same as the specific vibration frequency.

[0181] According to a wireless power transmission method by resonance
coupling, when the wireless power transmitter 100 and wireless power
receiver 200 resonate at the same frequency, respectively, an
electromagnetic wave is propagated through a short-range magnetic field,
and thus there exists no energy transfer between the devices if they have
different frequencies.

[0182] As a result, an efficiency of wireless power transmission by the
resonance coupling method is greatly affected by a frequency
characteristic, whereas the effect of an alignment and distance between
the wireless power transmitter 100 and the wireless power receiver 200
including each coil is relatively smaller than the inductive coupling
method.

[0183] Hereinafter, the configuration of a wireless power transmitter and
a wireless power receiver in the resonance coupling method applicable to
the embodiments disclosed herein will be described in detail.

[0184] Wireless power transmitter in resonance coupling method

[0185] FIG. 7 is a block diagram illustrating part of the wireless power
transmitter 100 and wireless power receiver 200 in a resonance method
that can be employed in the embodiments disclosed herein.

[0186] A configuration of the power transmission unit 110 included in the
wireless power transmitter 100 will be described with reference to FIG.
7A.

[0187] The power conversion unit 111 of the wireless power transmitter 100
may include a transmitting (Tx) coil 1111b, an inverter 1112, and a
resonant circuit 1116. The inverter 1112 may be configured to be
connected to the transmitting coil 1111b and the resonant circuit 1116.

[0188] The transmitting coil 1111b may be mounted separately from the
transmitting coil 1111a for transferring power according to the inductive
coupling method, but may transfer power in the inductive coupling method
and resonance coupling method using one single coil.

[0189] The transmitting coil 1111b, as described above, forms a magnetic
field for transferring power. The transmitting coil 1111b and the
resonant circuit 1116 generate resonance when alternating current power
is applied thereto, and at this time, a vibration frequency may be
determined based on an inductance of the transmitting coil 1111b and a
capacitance of the resonant circuit 1116.

[0190] For this purpose, the inverter 1112 transforms a DC input obtained
from the power supply unit 190 into an AC waveform, and the transformed
AC current is applied to the transmitting coil 1111b and the resonant
circuit 1116.

[0191] In addition, the power conversion unit 111 may further include a
frequency adjustment unit 1117 for changing a resonance frequency of the
power conversion unit 111. The resonance frequency of the power
conversion unit 111 is determined based on an inductance and/or
capacitance within a circuit constituting the power conversion unit 111
by Equation 1, and thus the power transmission control unit 112 may
determine the resonance frequency of the power conversion unit 111 by
controlling the frequency adjustment unit 1117 to change the inductance
and/or capacitance.

[0192] The frequency adjustment unit 1117, for example, may be configured
to include a motor for adjusting a distance between capacitors included
in the resonant circuit 1116 to change a capacitance, or include a motor
for adjusting a number of turns or diameter of the transmitting coil
1111b to change an inductance, or include active elements for determining
the capacitance and/or inductance

[0193] On the other hand, the power conversion unit 111 may further
include a power sensing unit 1115. The operation of the power sensing
unit 1115 is the same as the foregoing description.

[0194] Referring to FIG. 7B, a configuration of the power supply unit 290
included in the wireless power receiver 200 will be described. The power
supply unit 290, as described above, may include the receiving (Rx) coil
2911b and resonant circuit 2912.

[0195] In addition, the power receiving unit 291 of the power supply unit
290 may further include a rectifier circuit 2913 for converting an AC
current generated by resonance phenomenon into DC. The rectifier circuit
2913 may be configured similarly to the foregoing description.

[0196] Furthermore, the power receiving unit 291 may further include a
power sensing unit 2914 for monitoring a voltage and/or current of the
rectified power. The power sensing unit 2914 may be configured similarly
to the foregoing description.

[0197] Wireless Power Transmitter Configured to Include One or More
Transmitting Coils

[0198] FIG. 8 is a block diagram illustrating a wireless power transmitter
configured to have one or more transmission coils receiving power
according to an resonance coupling method that can be employed in the
embodiments disclosed herein.

[0199] Referring to FIG. 8, the power conversion unit 111 of the wireless
power transmitter 100 according to the embodiments disclosed herein may
include one or more transmitting coils 1111b-1 to 1111b-n and resonant
circuits (1116-1 to 1116-n) connected to each transmitting coils.
Furthermore, the power conversion unit 111 may further include a
multiplexer 1113 for establishing and releasing the connection of some of
the one or more transmitting coils 1111b-1 to 1111b-n.

[0200] The one or more transmitting coils 1111b-1 to 1111b-n may be
configured to have the same vibration frequency, or some of them may be
configured to have different vibration frequencies. It is determined by
an inductance and/or capacitance of the resonant circuits (1116-1 to
1116-n) connected to the one or more transmitting coils 1111b-1 to
1111b-n, respectively.

[0201] For this purpose, the frequency adjustment unit 1117 may be
configured to change an inductance and/or capacitance of the resonant
circuits (1116-1 to 1116-n) connected to the one or more transmitting
coils 1111b-1 to 1111b-n, respectively.

[0202] In-Band Communication

[0203]FIG. 9 is a view illustrating the concept of transmitting and
receiving a packet between a wireless power transmitter and an electronic
device through the modulation and demodulation of a wireless power signal
in wireless power transfer according to the embodiments disclosed herein.

[0204] Referring to FIG. 9, the power conversion unit 111 included in the
wireless power transmitter 100 forms a wireless power signal. The
wireless power signal is formed through the transmitting coil 1111
included in the power conversion unit 111.

[0205] A wireless power signal 10a formed by the power conversion unit 111
arrives at the electronic device 200, and received through the power
receiving unit 291 included in the electronic device 200. The formed
wireless power signal is received through the a receiving coil 2911
included in the power receiving unit 291.

[0206] The power receiving control unit 292 controls the
modulation/demodulation unit 293 connected to the power receiving unit
291 to modulate the wireless power signal while the electronic device 200
receives the wireless power signal. When the received wireless power
signal is modulated, the wireless power signal forms a closed-loop within
a magnetic field or electromagnetic field, and therefore, the wireless
power transmitter 100 may detect the modulated wireless power signal 10b.
The modulation/demodulation unit 113 may demodulates the detected
wireless power signal, and decodes the packet from the modulated wireless
power signal.

[0207] On the other hand, a modulation method used for communication
between the wireless power transmitter 100 and the electronic device 200
may be amplitude modulation. As described above, the amplitude modulation
method may be a backscatter modulation method in which the power
communications modulation/demodulation unit 293 at the side of the
electronic device 200 changes an amplitude of the wireless power signal
10a formed by the power conversion unit 111 and the power receiving
control unit 292 at the side of the wireless power transmitter 100
detects an amplitude of the modulated wireless power signal 10b.

[0208] Modulation and Demodulation of Wireless Power Signal

[0209] Hereinafter, the modulation and demodulation of a packet
transmitted and received between the wireless power transmitter 100 and
the electronic device 200 will be described with reference to FIGS. 10
and 11.

[0210]FIG. 10 is a view illustrating the configuration of transmitting
and receiving a power control message in wireless power transfer
according to the embodiments disclosed herein, and FIG. 11 is a view
illustrating the form of a signal in the modulation and demodulation
carried out in wireless power transfer according to the embodiments
disclosed herein.

[0211] Referring to FIG. 10, the wireless power signal received through
the power receiving unit 291 at the side of the electronic device 200 is
a wireless power signal 51 that is not modulated as illustrated in FIG.
11A. A resonance coupling between the electronic device 200 and the
wireless power transmitter 100 is implemented according to a resonant
frequency set by the resonant formation circuit 2912 within the power
receiving unit 291, and the wireless power signal 51 is received through
the receiving coil 2911b.

[0212] The power receiving control unit 292 modulates the wireless power
signal 51 received through the power receiving unit 291 by changing a
load impedance within the power communications modulation/demodulation
unit 293. The power receiving control unit 292 may include a passive
element 2931 and an active element 2932 for modulating the wireless power
signal 51. The modulation/demodulation unit 293 modulates the wireless
power signal 51 to include a packet desired to be transmitted to the
wireless power transmitter 100. At this time, the packet may be input to
the active element 2932 within the power communications
modulation/demodulation unit 293.

[0213] Then, the power transmission control unit 112 at the side of the
wireless power transmitter 100 demodulates the modulated wireless power
signal 52 through an envelope detection process, and decodes the detected
signal 53 into digital data 54. The demodulation process detects a
current or voltage flowing into the power conversion unit 111 to be
classified into two states, a HI state and a LO state, and acquires a
packet to be transmitted by the electronic device 200 based on digital
data classified according to the states.

[0214] Hereinafter, a process in which the wireless power transmitter 100
acquires a power control message to be transmitted by the electronic
device 200 from the modulated digital data will be described.

[0215] Referring to FIG. 11B, the power transmission control unit 112
detects an encoded bit using a clock signal (CLK) from an envelope
detected signal. The detected encoded bit is encoded according to a bit
encoding method used in the modulation process at the side of the
electronic device 200. In some embodiments, the bit encoding method may
be non-return to zero (NRZ). In some embodiments, the bit encoding method
may bi-phase encoding.

[0216] For instance, the detected bit may be a differential bi-phase (DBP)
encoded bit. According to the DBP encoding, the power receiving control
unit 292 at the side of the electronic device 200 is allowed to have two
state transitions to encode data bit 1, and to have one state transition
to encode data bit 0. In other words, data bit 1 may be encoded in such a
manner that a transition between the HI state and LO state is generated
at a rising edge and falling edge of the clock signal, and data bit 0 may
be encoded in such a manner that a transition between the HI state and LO
state is generated at a rising edge of the clock signal.

[0217] On the other hand, the power transmission control unit 112 may
acquire data in a byte unit using a byte format constituting a packet
from a bit string detected according to the bit encoding method. For
instance, the detected bit string may be transferred by using a 11-bit
asynchronous serial format as illustrated in FIG. 11C. In other words,
the detected bit may include a start bit indicating the beginning of a
byte and a stop bit indicating the end of a byte, and also include data
bits (b0 to b7) between the start bit and the stop bit. Furthermore, it
may further include a parity bit for checking an error of data. The data
in a byte unit constitutes a packet including a power control message.

[0218] [In Case of Supporting in-Band Two-Way Communication]

[0219] As described above, FIG. 9 has illustrated that the wireless power
receiver 200 transmits a packet using a carrier signal 10a formed by the
wireless power transmitter 100, but the wireless power transmitter 100
can also transmit data to the wireless power receiver 200 in a similar
manner as described above.

[0220] In other words, the power transmission control unit 112 may control
the modulation/demodulation unit 113 such that data to be sent to the
wireless power receiver 200 is loaded on the carrier signal 10a. In this
case, the power receiving control unit 292 at the side of the wireless
power receiver 200 may control the power communications
modulation/demodulation unit 293 to acquire data from the to modulated
carrier signal 10a.

[0221] Packet Format

[0222] Hereinafter, the structure of a packet used in communication using
a wireless power signal according to the embodiments disclosed herein
will be described.

[0223]FIG. 12 is a view illustrating a packet including a power control
message used in a contactless power transfer method according to the
embodiments disclosed herein.

[0224] Referring to FIG. 12A, the wireless power transmitter 100 and the
electronic device 200 may transmit and receive data desired to be
transmitted in the form of a command packet 510. The command packet 510
may include a header 511 and a message 512.

[0225] The header 511 may include a field indicating the kind of data
contained in the message 512. The size and kind of the message can be
determined based on a value indicated by the field indicating the kind of
data.

[0226] Furthermore, the header 511 may include an address field capable of
identifying the sender of the packet. For instance, the address field may
indicate an identifier of the electronic device 200 or an identifier of
the group to which the electronic device 200 belongs. When the electronic
device 200 desires to transmit the packet 510, the electronic device 200
may generate the packet 510, thereby allowing the address field of the
packet 510 to indicate its own identification information.

[0227] The message 512 may include data desired to be transmitted by the
sender of the packet 510. The data contained in the message 512 may be a
report, a request or a response.

[0228] On the other hand, in some embodiments, the command packet 510 may
be configured as illustrated in FIG. 12B. The header 511 contained in the
command packet 510 may be expressed with a predetermined size. For
instance, the header 511 may be the size of two bytes.

[0229] The header 511 may be configured to contain a receiver address
field. For instance, the receiver address field may be the size of 6
bytes.

[0230] The header 511 may include an operation command field (OCF) or
operation group field (OGF). The OGF is a value given for each group of
commands for the electronic device 200, and the OCF is a value given for
each command existing in each group containing the electronic device 200.

[0231] The message 512 may be expressed by dividing into a length field
5121 of the parameter and a value field 5122 of the parameter. In other
words, the sender of the packet 510 may be configured in the form of one
or more pairs of length-value of the parameters required to express data
desired to transmit the message.

[0232] Referring to FIG. 12C, the wireless power transmitter 100 and the
electronic device 200 may transmit and receive the data in the form of a
packet in which the preamble 520 and checksum 530 for transmission are
added to the command packet 510.

[0233] The preamble 520 may be used to perform synchronization with data
received by the wireless power transmitter 100 and correctly detect the
start bit of the command packet 510. The preamble 520 may be configured
to repeat the same bit. For instance, the preamble 520 may be configured
such that data bit 1 according to the DBP encoding is repeated eleven to
twenty five times.

[0234] The checksum 530 may be used to detect an error that can be
occurred in the command packet 510 while transmitting a power control
message.

[0235] Operation Phases

[0236] Hereinafter, the operation phases of the wireless power transmitter
100 and wireless power receiver 200 will be described.

[0237]FIG. 13 illustrates the operation phases of the wireless power
transmitter 100 and wireless power receiver 200 according to the
embodiments disclosed herein. Furthermore, FIGS. 14 through 18 illustrate
the structure of packets including a power control message between the
wireless power transmitter 100 and wireless power receiver 200.

[0238] Referring to FIG. 13, the operation phases of the wireless power
transmitter 100 and the wireless power receiver 200 for contactless power
transfer may be divided into a selection state (or phase) 610, a Ping
state (or phase) 620, an Identification and configuration state (or
phase) 630, and a Power transfer state (or phase) 640.

[0239] The wireless power transmitter 100 detects whether or not objects
exist within a range that the wireless power transmitter 100 can transmit
power in a wireless manner in the selection state (or phase) 610, and the
wireless power transmitter 100 sends a detection signal to the detected
object and the wireless power receiver 200 sends a response to the
detection signal in the Ping state (or phase) 620.

[0240] Furthermore, the wireless power transmitter 100 identifies the
wireless power receiver 200 selected through the previous states and
acquires configuration information for power transfer in the
Identification and configuration state (or phase) 630. The wireless power
transmitter 100 transmits power to the wireless power receiver 200 while
controlling power transmitted in response to a control message received
from the wireless power receiver 200 in the Power transfer state (or
phase) 640.

[0241] Hereinafter, each of the operation phases will be described in
detail.

[0242] 1) Selection State (or Phase)

[0243] The wireless power transmitter 100 in the selection state (or
phase) 610 performs a detection process to select the wireless power
receiver 200 existing within a detection area. The detection area, as
described above, refers to a region in which an object within the
relevant area can affect on the characteristic of the power of the power
conversion unit 111. Compared to the Ping state (or phase) 620, the
detection process for selecting the wireless power receiver 200 in the
selection state (or phase) 610 is a process of detecting a change of the
power amount for forming a wireless power signal in the power conversion
unit at the side of the wireless power transmitter 100 to check whether
any object exists within a predetermined range, instead of the scheme of
receiving a response from the wireless power receiver 200 using a power
control message. The detection process in the selection state (or phase)
610 may be referred to as an analog ping process in the aspect of
detecting an object using a wireless power signal without using a packet
in a digital format in the Ping state (or phase) 620 which will be
described later.

[0244] The wireless power transmitter 100 in the selection state (or
phase) 610 can detect that an object comes in or out within the detection
area. Furthermore, the wireless power transmitter 100 can distinguish the
wireless power receiver 200 capable of transferring power in a wireless
manner from other objects (for example, a key, a coin, etc.) among
objects located within the detection area.

[0245] As described above, a distance that can transmit power in a
wireless manner may be different according to the inductive coupling
method and resonance coupling method, and thus the detection area for
detecting an object in the selection state (or phase) 610 may be
different from one another.

[0246] First, in case where power is transmitted according to the
inductive coupling method, the wireless power transmitter 100 in the
selection state (or phase) 610 can monitor an interface surface (not
shown) to detect the alignment and removal of objects.

[0247] Furthermore, the wireless power transmitter 100 may detect the
location of the wireless power receiver 200 placed on an upper portion of
the interface surface. As described above, the wireless power transmitter
100 formed to include one or more transmitting coils may perform the
process of entering the Ping state (or phase) 620 in the selection state
(or phase) 610, and checking whether or not a response to the detection
signal is transmitted from the object using each coil in the Ping state
(or phase) 620 or subsequently entering the identification state 630 to
check whether identification information is transmitted from the object.
The wireless power transmitter 100 may determine a coil to be used for
contactless power transfer based on the detected location of the wireless
power receiver 200 acquired through the foregoing process.

[0248] Furthermore, when power is transmitted according to the resonance
coupling method, the wireless power transmitter 100 in the selection
state (or phase) 610 can detect an object by detecting that any one of a
frequency, a current and a voltage of the power conversion unit is
changed due to an object located within the detection area.

[0249] On the other hand, the wireless power transmitter 100 in the
selection state (or phase) 610 may detect an object by at least any one
of the detection methods using the inductive coupling method and
resonance coupling method. The wireless power transmitter 100 may perform
an object detection process according to each power transmission method,
and subsequently select a method of detecting the object from the
coupling methods for contactless power transfer to advance to other
states 620, 630, 640.

[0250] On the other hand, for the wireless power transmitter 100, a
wireless power signal formed to detect an object in the selection state
(or phase) 610 and a wireless power signal formed to perform digital
detection, identification, configuration and power transmission in the
subsequent states 620, 630, 640 may have a different characteristic in
the frequency, strength, and the like. It is because the selection state
(or phase) 610 of the wireless power transmitter 100 corresponds to an
idle phase for detecting an object, thereby allowing the wireless power
transmitter 100 to reduce consumption power in the idle state or generate
a specialized signal for effectively detecting an object.

[0251] 2) Ping State (or Phase)

[0252] The wireless power transmitter 100 in the Ping state (or phase) 620
performs a process of detecting the wireless power receiver 200 existing
within the detection area through a power control message. Compared to
the detection process of the wireless power receiver 200 using a
characteristic of the wireless power signal and the like in the selection
state (or phase) 610, the detection process in the Ping state (or phase)
620 may be referred to as a digital ping process.

[0253] The wireless power transmitter 100 in the Ping state (or phase) 620
forms a wireless power signal to detect the wireless power receiver 200,
modulates the wireless power signal modulated by the wireless power
receiver 200, and acquires a power control message in a digital data
format corresponding to a response to the detection signal from the
modulated wireless power signal. The wireless power transmitter 100 may
receive a power control message corresponding to the response to the
detection signal to recognize the wireless power receiver 200 which is a
subject of power transmission.

[0254] The detection signal formed to allow the wireless power transmitter
100 in the Ping state (or phase) 620 to perform a digital detection
process may be a wireless power signal formed by applying a power signal
at a specific operating point for a predetermined period of time. The
operating point may denote a frequency, duty cycle, and amplitude of the
voltage applied to the transmitting (Tx) coil. The wireless power
transmitter 100 may generate the detection signal generated by applying
the power signal at a specific operating point for a predetermined period
of time, and attempt to receive a power control message from the wireless
power receiver 200.

[0255] On the other hand, the power control message corresponding to a
response to the detection signal may be a message indicating a strength
of the wireless power signal received by the wireless power receiver 200.
For example, the wireless power receiver 200 may transmit a signal
strength packet 5100 including a message indicating the received strength
of the wireless power signal as a response to the detection signal as
illustrated in FIG. 14. The packet 5100 may include a header 5120 for
notifying a packet indicating the signal strength and a message 5130
indicating a strength of the power signal received by the wireless power
receiver 200. The strength of the power signal within the message 5130
may be a value indicating a degree of inductive coupling or resonance
coupling for power transmission between the wireless power transmitter
100 and the wireless power receiver 200.

[0256] The wireless power transmitter 100 may receive a response message
to the detection signal to find the wireless power receiver 200, and then
extend the digital detection process to enter the Identification and
configuration state (or phase) 630. In other words, the wireless power
transmitter 100 maintains the power signal at a specific operating point
subsequent to finding the wireless power receiver 200 to receive a power
control message required in the Identification and configuration state
(or phase) 630.

[0257] However, if the wireless power transmitter 100 is not able to find
the wireless power receiver 200 to which power can be transferred, then
the operation phase of the wireless power transmitter 100 will be
returned to the selection state (or phase) 610.

[0258] 3) Identification and Configuration State (or Phase)

[0259] The wireless power transmitter 100 in the Identification and
configuration state (or phase) 630 may receive identification information
and/or configuration information transmitted by the wireless power
receiver 200, thereby controlling power transfer to be effectively
carried out.

[0260] The wireless power receiver 200 in the Identification and
configuration state (or phase) 630 may transmit a power control message
including its own identification information. For this purpose, the
wireless power receiver 200, for instance, may transmit an identification
packet 5200 including a message indicating the identification information
of the wireless power receiver 200 as illustrated in FIG. 15A. The packet
5200 may include a header 5220 for notifying a packet indicating
identification information and a message 5230 including the
identification information of the wireless power receiver. The message
5230 may include information (2531 and 5232) indicating a version of the
contract for contactless power transfer, information 5233 for identifying
a manufacturer of the wireless power receiver 200, information 5234
indicating the presence or absence of an extended device identifier, and
a basic device identifier 5235. Furthermore, if it is displayed that an
extended device identifier exists in the information 5234 indicating the
presence or absence of an extended device identifier, then an extended
identification packet 5300 including the extended device identifier as
illustrated in FIG. 15B will be transmitted in a separate manner. The
packet 5300 may include a header 5320 for notifying a packet indicating
an extended device identifier and a message 5330 including the extended
device identifier. When the extended device identifier is used as
described above, information based on the manufacturer's identification
information 5233, the basic device identifier 5235 and the extended
device identifier 5330 will be used to identify the wireless power
receiver 200.

[0261] The wireless power receiver 200 may transmit a power control
message including information on expected maximum power in the
Identification and configuration state (or phase) 630. To this end, the
wireless power receiver 200, for instance, may transmit a configuration
packet 5400 as illustrated in FIG. 16. The packet may include a header
5420 for notifying that it is a configuration packet and a message 5430
including information on the expected maximum power. The message 5430 may
include power class 5431, information 5432 on expected maximum power, an
indicator 5433 indicating a method of determining a current of a main
cell at the side of the wireless power transmitter, and the number 5434
of optional configuration packets. The indicator 5433 may indicate
whether or not a current of the main cell at the side of the wireless
power transmitter is determined as specified in the contract for
contactless power transfer.

[0262] On the other hand, the wireless power transmitter 100 may generate
a power transfer contract which is used for power charging with the
wireless power receiver 200 based on the identification information
and/or configuration information. The power transfer contract may include
the limits of parameters determining a power transfer characteristic in
the Power transfer state (or phase) 640.

[0263] The wireless power transmitter 100 may terminate the Identification
and configuration state (or phase) 630 and return to the selection state
(or phase) 610 prior to entering the Power transfer state (or phase) 640.
For instance, the wireless power transmitter 100 may terminate the
Identification and configuration state (or phase) 630 to find another
wireless power receiver that can receive power in a wireless manner.

[0264] 4) Power Transfer State (or Phase)

[0265] The wireless power transmitter 100 in the Power transfer state (or
phase) 640 transmits power to the wireless power receiver 200.

[0266] The wireless power transmitter 100 may receive a power control
message from the wireless power receiver 200 while transmitting power,
and control a characteristic of the power applied to the transmitting
coil in response to the received power control message. For example, the
power control message used to control a characteristic of the power
applied to the transmitting coil may be included in a control error
packet 5500 as illustrated in FIG. 17. The packet 5500 may include a
header 5520 for notifying that it is a control error packet and a message
5530 including a control error value. The wireless power transmitter 100
may control the power applied to the transmitting coil according to the
control error value. In other words, a current applied to the
transmitting coil may be controlled so as to be maintained if the control
error value is "0", reduced if the control error value is a negative
value, and increased if the control error value is a positive value.

[0267] The wireless power transmitter 100 may monitor parameters within a
power transfer contract generated based on the identification information
and/or configuration information in the Power transfer state (or phase)
640. As a result of monitoring the parameters, if power transmission to
the wireless power receiver 200 violates the limits included in the power
transfer contract, then the wireless power transmitter 100 may cancel the
power transmission and return to the selection state (or phase) 610.

[0268] The wireless power transmitter 100 may terminate the Power transfer
state (or phase) 640 based on a power control message transferred from
the wireless power receiver 200.

[0269] For example, if the charging of a battery has been completed while
charging the battery using power transferred by the wireless power
receiver 200, then a power control message for requesting the suspension
of contactless power transfer will be transferred to the wireless power
transmitter 100. In this case, the wireless power transmitter 100 may
receive a message for requesting the suspension of the power
transmission, and then terminate contactless power transfer, and return
to the selection state (or phase) 610.

[0270] For another example, the wireless power receiver 200 may transfer a
power control message for requesting renegotiation or reconfiguration to
update the previously generated power transfer contract. The wireless
power receiver 200 may transfer a message for requesting the
renegotiation of the power transfer contract when it is required a larger
or smaller amount of power than the currently transmitted power amount.
In this case, the wireless power transmitter 100 may receive a message
for requesting the renegotiation of the power transfer contract, and then
terminate contactless power transfer, and return to the Identification
and configuration state (or phase) 630.

[0271] To this end, a message transmitted by the wireless power receiver
200, for instance, may be an end power transfer packet 5600 as
illustrated in FIG. 18. The packet 5600 may include a header 5620 for
notifying that it is an end power transfer packet and a message 5630
including an end power transfer code indicating the cause of the
suspension. The end power transfer code may indicate any one of charge
complete, internal fault, over temperature, over voltage, over current,
battery failure, reconfigure, no response, and unknown error.

[0272] Communication Method of a Plurality of Electronic Devices

[0273] Hereinafter, a method in which one or more electronic devices
perform communication using a wireless power signal from one wireless
power transmitter will be described.

[0274]FIG. 19 is a conceptual view illustrating a method in which a
wireless power transmitter transfers power to one or more wireless power
receivers.

[0275] The wireless power transmitter 100 may transfer power for one or
more wireless power receivers 200, 200'. In FIG. 19, two electronic
devices 200, 200' are illustrated, but the foregoing method according to
the embodiments disclosed herein will not be limited to the number of
electronic devices illustrated herein.

[0276] The active region and detection region are different according to a
wireless power transfer scheme of the wireless power transmitter 100.
Accordingly, the wireless power transmitter 100 may determine whether
there exists a wireless power receiver disposed in the active region or
detection region of the resonant coupling method or whether there exists
a wireless power receiver disposed in the active region or detection
region of the inductive coupling method. According to a result of the
determination, the wireless power transmitter 100 supporting each
wireless power transfer scheme may change the power transfer scheme for
each wireless power receiver.

[0277] According to wireless power transfer according to the embodiments
disclosed herein, when the wireless power transmitter 100 transfers power
for one or more electronic devices 200, 200' with the same wireless power
transfer scheme, communication may be carried out through the wireless
power signal without being collided with each other.

[0278] As illustrated in FIG. 19, the wireless power signal 10a formed by
the wireless power transmitter 100 arrives at a first electronic device
200' and a second electronic device 200. The first electronic device 200'
and second electronic device 200 may transmit a power control message
using the formed wireless power signal.

[0279] The first electronic device 200' and second electronic device 200
are operated as power receivers for receiving a wireless power signal.
The power receiver according to the embodiments disclosed herein may
include a power receiving unit 291', 291 for receiving the formed
wireless power signal; a modulation/demodulation unit 293', 293 for
performing modulation and demodulation for the received wireless power
signal; and a controller 292', 292' for controlling each constituent
elements of the power receiver.

[0280] [In Case of Supporting in-Band Two-Way Communication]

[0281] Hereinafter, a method of recognizing a wireless power receiver
using two-way communication in wireless power transfer according to the
embodiments disclosed herein will be described.

[0283] FIGS. 20A through 20C are conceptual views illustrating a two-way
communication process between a wireless power transmitter 100 and one or
more wireless power receivers 200 according to an embodiment disclosed
herein.

[0284] Referring to FIGS. 20A through 20C, the wireless power transmitter
100 transmits a request message to the wireless power receiver 200. For
example, the power transmission control unit 112 generates a packet
containing a request message for the wireless power receiver 200, and the
modulation/demodulation unit 113 modulates a wireless power signal to
contain the generated packet, and the power conversion unit 111 transmits
the modulated wireless power signal to the wireless power receiver 200.
Furthermore, the power receiving unit 291 receives a wireless power
signal from the wireless power transmitter 100, and the
modulation/demodulation unit 293 demodulates a packet from the received
wireless power signal, and the power receiving control unit 292 may
acquire a request message contained in the packet.

[0285] The power receiving control unit 292 transmits a response message
to the wireless power transmitter 100 within a predetermined period of
time after receiving a request message (responds to the transmitting unit
with a modulation method of load change). For example, the power
receiving control unit 292 generates a packet containing a response
message to the wireless power transmitter 100, and the
modulation/demodulation unit 293 modulates a wireless power signal to
contain the generated packet, and the power receiving unit 291 transmits
the modulated wireless power signal to the wireless power transmitter
100. Furthermore, the power receiving unit 291 receives a wireless power
signal from the wireless power receiver 200, and the
modulation/demodulation unit 113 modulates a packet from the received
wireless power signal, and the power transmission control unit 112 may
acquire a response message contained in the packet (detects an impedance
change of the receiving unit generated by a load change with a response
signal).

[0286] When the identification information of a specific wireless power
receiver, for example, address, is contained in the request message, only
the wireless power receivers corresponding to the relevant identification
information may transmit a response message to the wireless power
transmitter 100 in response to the request message of the wireless power
transmitter 100.

[0287] Furthermore, communication may be carried out using a method of
transmitting and receiving a message on one communication line between
the wireless power transmitter 100 and the wireless power receiver 200.

First Embodiment

[0288] Hereinafter, a method of recognizing an initial wireless power
receiver in two-way communication of wireless power transfer according to
a first embodiment disclosed herein will be described.

[0289] FIGS. 21A through 21G are conceptual views illustrating a process
in which a wireless power transmitter 100 recognizes a wireless power
receiver 200 at the initial stage in wireless power transfer supporting
two-way communication.

[0290] Referring to FIG. 21A, a RX detection phase is carried out. the
wireless power transmitter 100 transmits detection power to a plurality
of wireless power receivers 200-1 to 200-n, thereby allowing the wireless
power receivers 200-1 to 200-n to be switched from a sleep mode to an
operating mode (wake-up). When transmitting detection power, the wireless
power transmitter 100 requests the identification information (ID) of
each wireless power receiver (ID request).

[0291] Referring to FIGS. 21B and 21C, a RX response phase is carried out.
A plurality of wireless power receivers 200-1 to 200-n switched to an
operating mode by the wireless power transmitter 100 responds to the
wireless power transmitter 100 based on their own individual delay times.
In other words, the first wireless power receiver 200-1 through the n-th
wireless power receiver 200-n time-divide a response delay time based on
each random number subsequent to device start or operating mode start (ID
respond).

[0292] In particular, referring to FIG. 21c, when the wireless power
receivers 200-1 to 200-n located within a detection range respond to a
request of the wireless power transmitter 100, a collided response signal
may exist on the signal according to each random number.

[0293] Referring to FIG. 21D, a TX/RX register phase is carried out. The
wireless power transmitter 100 performs an authentication process for a
valid signal (a signal capable of acquiring the identification
information of the wireless power receiver 200) among the signals sent
from the wireless power receivers 200-1 to 200-n, and then registers it
with the wireless power transmitter 100. Then, the registered wireless
power receiver 200-2 is switched to a sleep mode, thereby not allowing to
respond when identification information is requested again to the
wireless power receivers 200-1 to 200-n.

[0294] Referring to FIG. 21E, a RX re-detection phase is carried out. The
wireless power transmitter 100 transmits wireless power for requesting
identification information again to a plurality of wireless power
receivers 200-1 to 200-n to detect the remaining wireless power
receivers, namely, non-registered wireless power receivers 200-1, 200-n.

[0295] Referring to FIG. 21F, a RX re-respond phase is carried out.
Excluding the wireless power receiver 200-2 switched to a sleep mode (a
wireless power receiver registered with the wireless power transmitter
100), they respond based on their own individual delay times. In other
words, the first wireless power receiver 200-1 through the n-th wireless
power receiver 200-n time-divide a response delay time based on each
random number subsequent to device start or operating mode start (ID
respond).

[0296] Referring to FIG. 21G, a TK/RK register phase is carried out. The
wireless power transmitter 100 performs an authentication process for a
valid signal (acquired identification information) among the signals sent
from the wireless power receivers 200-1 to 200-n, and then registers it
with the wireless power transmitter 100. Then, the registered wireless
power receiver 200-1 is switched to a sleep mode, thereby not allowing to
respond when identification information is requested. When there is no
response even when identification information is requested to the
wireless power receivers 200-1 to 200-n, the wireless power transmitter
100 is changed from a detection phase to a power transfer phase, thereby
performing communication using a handshaking scheme with the wireless
power receiver 200 based on each identification information.

[0297] FIG. 22 is a flow chart illustrating a process in which a wireless
power transmitter 100 recognizes a wireless power receiver 200 at the
initial stage in wireless power transfer supporting two-way
communication.

[0298] The wireless power transmitter 100 requests identification
information (or address) to the wireless power receiver 200 (S110), and
performs a register phase for valid (not being collided, signal can be
received at the wireless power receiver 200) wireless power receivers 200
(S120 to S140). In other words, the wireless power transmitter 100
determines whether there exists any responding wireless power receiver
200 (S120), determines whether there exists any valid wireless power
receiver 200 when there exists any responding wireless power receiver 200
(S130), and registers the relevant wireless power receiver 200 with the
wireless power transmitter 100 when there exists any valid wireless power
receiver 200 (S150).

[0299] A sleep mode change is requested for the registered wireless power
receiver 200 (S150), and the wireless power transmitter 100 requests
identification information (address) again for the remaining
(non-registered) wireless power receiver 200.

[0300] During the identification information request, the wireless power
receivers 200 send information to the wireless power transmitter 100 to
be time-divided by their own random numbers, respectively, and a register
phase is carried out in the wireless power transmitter 100 for a signal
of the wireless power receiver 200 that has not been collapsed.

[0301] When detection for all wireless power receivers 200 has been
completed (when there is no more response to a detection request of the
wireless power transmitter 100), power transfer communication is carried
out based on the registered wireless power receiver address (S160).

[0302]FIG. 23 is a view illustrating the phase change of a wireless power
transmitter 100 during a process in which the wireless power transmitter
100 recognizes a wireless power receiver 200 at the initial stage in
wireless power transfer supporting two-way communication.

[0303] The wireless power transmitter 100 detects the wireless power
receiver 200 at the initial stage in a selection state (or phase) (S210)
and requests identification information to receive the identification
information from the wireless power receiver 200 (S220). When there
exists any valid wireless power receiver 200, the wireless power
transmitter 100 registers the relevant wireless power receiver 200, and
transmits the assigned ID to the wireless power receiver 200 (S230). At
this time, the wireless power transmitter 100 manages the wireless power
receiver 200, and perform power transfer communication with the wireless
power receiver 200 (S240). When a new wireless power receiver 200 is
added thereto, the wireless power transmitter 100 is switched to the step
S220. However, when there does not exist a new wireless power receiver
200, the wireless power transmitter 100 is switched to the step S210.

[0304]FIG. 24 is a view illustrating an operation process between a
wireless power transmitter 100 and a wireless power receiver 200 during a
process in which the wireless power transmitter 100 recognizes a wireless
power receiver 200 at the initial stage in wireless power transfer
supporting two-way communication.

[0305] The wireless power transmitter 100 performs low power transfer for
waking up the wireless power receiver 200 to an operating mode. In other
words, analog ping is transferred from the wireless power transmitter 100
to the wireless power receiver 200, and switched to an operating mode,
and thus the control unit (MCU) is switched to an operating mode to
initialize communication (S310).

[0306] Accordingly, the wireless power receiver 200 transmits approach
identification information (address) to the wireless power transmitter
100. In other words, a register request message is transferred from the
wireless power receiver 200 to the wireless power transmitter 100, and
the wireless power transmitter 100 registers an address of the wireless
power receiver 200, assigns ID, and assigns a time slot (S320) to
transmit it to the wireless power receiver 200. A charge request message
is transmitted from the wireless power transmitter 100 to the wireless
power receiver 200. The wireless power receiver 200 assigns a new address
with the assigned ID, and transfers power to the charger 298 (S330).

[0307] The wireless power transmitter 100 requests a status of the
wireless power receiver 200 (S340), and checks a response from the
wireless power receiver 200 at each time slot (waits for a response). The
wireless power receiver 200 responds at each assigned time slot (S350).

[0308] The wireless power receiver 200 transmits charging information to
the wireless power transmitter 100. The wireless power receiver 200
starts the control of wireless power reception subsequent to a command of
the wireless power transmitter 100. If there is no command from the
wireless power transmitter 100, then the wireless power receiver 200
suspends power transfer to the charger 298.

[0309] If there is not response from the wireless power receiver 200, then
the wireless power transmitter 100 deletes the relevant wireless power
receiver 200 from a registration list.

[0310] FIGS. 25A through 25D are conceptual views illustrating a process
in which a wireless power transmitter 100 and a wireless power receiver
200 perform a request and response operation on various conditions in
wireless power transfer supporting two-way communication.

[0311]FIG. 25A illustrates a process in which the wireless power
transmitter 100 and wireless power receiver 200 transmit and receive a
request and response signal in case where a new wireless power receiver
200 approaches when there does not exist the wireless power receiver 200.

[0312]FIG. 25B illustrates a process in which the wireless power
transmitter 100 and wireless power receiver 200 transmit and receive a
request and response signal in case where a new wireless power receiver
200 approaches when there exists the wireless power receiver 200.

[0313]FIG. 25c illustrates a process in which the wireless power
transmitter 100 and wireless power receiver 200 transmit and receive a
request and response signal in case where new wireless power receivers
200 exist when the wireless power receiver 200 is turned on.

[0314]FIG. 25D illustrates a process in which the wireless power
transmitter 100 and wireless power receiver 200 transmit and receive a
request and response signal in case where new wireless power receivers
200 are collided when the wireless power receiver 200 is turned on.

[0315] FIGS. 26A through 26C are views illustrating a packet containing a
request/response message used during the two-way communication process
according to the embodiments disclosed herein.

[0316] Referring to FIG. 26A, the wireless power transmitter 100 and
electronic device 200 may transmit and receive the data in the form of a
packet in which a preamble 710, data 720, and an address 730 for
transmission are added to a request/response packet 700.

[0317] In case of a packet being transmitted from the wireless power
transmitter 100 using 100 ms to the wireless power receiver 200, it is
used, for example, to assign a 4-bit address to the wireless power
receiver 200 or request charging in the enum state, or transfer a status
and command request to the wireless power receiver 200 in a Power
transfer state (or phase).

[0318] Referring to FIG. 26B, 0x4d denotes that the assign ID of 0x0d is
given to the wireless power receiver 200 with the ID of 4, and 0x2d
denotes that ID indicates power off (0x02) to 0x0d.

[0319] In case of a packet being transmitted from the wireless power
receiver 200 using 20 ms to the wireless power transmitter 100, an
additional header (for example, 0x06) to the existing message may be
used. At this time, an address is inserted to the most significant 4-bit,
and data is inserted to the least significant 4-bit. During the approach,
the wireless power receiver 200 responds to the approach ID and time slot
based on a random value, and replies to a command of the wireless power
transmitter 100 at the assigned time subsequent to the approach ID being
assigned. FIG. 26c illustrates an exemplary structure of a packet being
transmitted from the wireless power receiver 200 to the wireless power
transmitter 100.

[0320] Referring to FIG. 24 again, when the wireless power receiver 200
requests registration with the wireless power transmitter 100 (S320), for
example, the header contains 0x06 with a value of the approach ID, and a
random value between 0 and 5, and the time slot will be any one between 0
and 5, and thus 0x06 0x04 shows data being transmitted from the fourth
time slot.

[0321] Then, when the wireless power transmitter 100 requests charging to
the wireless power receiver 200 (S330), for example, the packet contains
a 4-bit approach ID and a 4-bit assignment ID. For example, 0x4d shows
that the assignment ID with 0x0d is given to the wireless power receiver
200 with the ID of 4.

[0322] Then, when the wireless power transmitter 100 request a status
request to the wireless power receiver 200 (S340), the packet contains a
4-bit approach ID and a 4-bit status layer. For example, 0xf1 shows
making a request to all wireless power receivers 200, and 0xd2 shows
instructing power off to the wireless power receiver 200 with the ID of
0x0d.

[0323] Then, when the wireless power receiver 200 responds to the wireless
power transmitter 100 at the assigned time slot (S350), for example, 0x06
0xd2 shows that the wireless power receiver 200 with the ID of 0x0d
replies with 2.

[0324]FIG. 27 is a flow chart illustrating a process in which a wireless
power transmitter 100 transfers power to a wireless power receiver 200
through a command in wireless power transfer supporting two-way
communication.

[0325] Referring to FIG. 27, the wireless power transmitter 100 transmits
a synchronization signal for response to the first wireless power
receiver 200-1 (S412), and when a time slot for a newly added second
wireless power receiver 200-2 is assigned (S414), the first wireless
power receiver 200-1 and second wireless power receiver 200-2 transmit
their own information, respectively, to the wireless power transmitter
100 (S416, S418).

[0326] Furthermore, the wireless power transmitter 100 transmits a
non-synchronization signal for response to the first wireless power
receiver 200-1 (S422), and when a time slot for a newly added second
wireless power receiver 200-2 is assigned (S424), the first wireless
power receiver 200-1 and second wireless power receiver 200-2 transmit
their own information, respectively, to the wireless power transmitter
100 (S426, S428).

[0327] Furthermore, the wireless power transmitter 100 transmits a request
for a specific wireless power receiver to the first wireless power
receiver 200-1 (S432), and even when a time slot for a newly added second
wireless power receiver 200-2 is assigned (S434), only the first wireless
power receiver 200-1 transmits its own information to the wireless power
transmitter 100 (S436).

[0328]FIG. 28 is a conceptual view illustrating the phase change of a
wireless power transmitter 100 during the power transfer process
illustrated in FIG. 27.

[0329] The wireless power transmitter 100 may be switched from a state of
sending a synchronization signal for the wireless power receiver 200
responding to the wireless power receiver 200 (S510) to a state of
sending a non-synchronization signal for the responding wireless power
receiver 200 (S520) or switched in the opposite way. Furthermore, the
wireless power transmitter 100 may be switched from a state of sending a
synchronization signal for the wireless power receiver 200 responding to
the wireless power receiver 200 (S510) to a state of sending a request
signal for a specific wireless power receiver 200 (S520) or switched in
the opposite way.

Second Embodiment

[0330] Hereinafter, a method of recognizing a single or multiple wireless
power receiver(s) in two-way communication of wireless power transfer
according to a second embodiment disclosed herein will be described.

[0331]FIG. 29 is a schematic view for explaining a process in which a
wireless power transmitter 100 recognizes an initial approach of the
wireless power receiver 200 and supplies power during two-way
communication on single wireless power transfer.

[0332] During the detection section 812, when there does not exist the
wireless power receiver 200, the wireless power transmitter 100 supplies
only power, and when the wireless power receiver 200 responds within
Δtdetect, the ID received from the wireless power receiver 200
is registered to start two-way communication.

[0333] During the identification and configuration section 814, the
wireless power transmitter 100 sends a communication packet to the
relevant wireless power receiver 200 based on the ID received from the
wireless power receiver 200, and performs an identification and
configuration process for power supply connection.

[0334] When authentication is normally completed during the power transfer
section 816, the wireless power transmitter 100 performs communication
required for power supply with the wireless power receiver 200 to supply
power.

[0335]FIG. 30 is a schematic view for explaining the process of
recognizing an wireless power receiver 200 and performing communication
when the wireless power receiver 200 approaches while a wireless power
transmitter 100 performs two-way communication with another wireless
power receiver 200 during two-way communication on single wireless power
transfer.

[0336] During the detection section 822, when a new second wireless power
receiver 200-2 is approached in a situation that the first wireless power
receiver 200-1 performs communication, the second wireless power receiver
200-2 receives power for detection, and then has an authentication
procedure during the identification and configuration section 824 when
responded to the wireless power transmitter 100 within
Δtdetect. The first wireless power receiver 200-1 normally
responds according to a request of the wireless power transmitter 100.

[0337] During the identification and configuration section 824,
subsequently, the wireless power transmitter 100 first grants an ID to
the wireless power receiver 200-2 that has requested a connection (when
the ID is granted, it is transmitted to an address to which only a new
wireless power receiver, namely, the second wireless power receiver 200-2
can respond, and the connection is established through an identification
and configuration process between them.

[0338] During the power transfer section 826, when authentication is
normally completed, information exchange communication required for power
supply is carried out for multiple wireless power receivers 200-1, 200-2,
respectively, in a duplex (handshaking two-way communication) manner to
supply power.

[0339]FIG. 31 is a view illustrating an example of a message transmitted
and received between a wireless power transmitter 100 and a wireless
power receiver performing two-way communication.

[0340] A packet 900 contained in a message being transmitted and received
between the wireless power transmitter 100 and wireless power receiver
performing two-way communication may include a sync 910, a header 920, a
message 930, and a checksum 940.

[0341] The sync 910 with two bytes, for example, is contained in the
packet 900 to synchronize message transmission and reception between the
wireless power transmitter 100 and wireless power receiver 200, and
detect a correct start bit.

[0342] The header 920 with three bytes, for example, constitutes a command
packet together with the message 930. The message 930 may include a
parameter to constitute a command packet together with the header 920.
The command packet may include an address for receiving a message, OCF,
OGF, a parameter length, and parameter values.

[0343] The checksum 940 is contained in the packet 900 to detect an error
that can be occurred in a command packet while a message is transmitted.

[0344]FIG. 32 is a view illustrating a procedure in which a wireless
power transmitter 100 and a wireless power receiver 200 perform two-way
communication on a signal channel.

[0345] The wireless power transmitter 100 generates an inquiry message and
transmits it to the wireless power receiver 200 (S512). The wireless
power receiver 200 performs inquiry scan to transmit an response message
to the inquiry (inquiry response) to the wireless power transmitter 100
(S514).

[0346] The wireless power transmitter 100 generates a message for
requesting identification information and transmits it to the wireless
power receiver 200 (S522). The wireless power receiver 200 performs
identification scan to transmit a response message to the identification
information request (identification response) to the wireless power
transmitter 100 (S524).

[0348] The wireless power transmitter 100 transmits power in a wireless
manner (wireless power tx) to the wireless power receiver 200 through a
wireless power signal (S542). The wireless power receiver 200 transmits a
status message of the wireless power receiver 200 (rx status) to the
wireless power transmitter 100 (S544).

[0349] The wireless power transmitter 100 transmits a message indicating
the termination of wireless power transfer (close) to the wireless power
receiver 200 (S552). The wireless power receiver 200 transmits a status
message of the wireless power receiver 200 (rx status) to the wireless
power transmitter 100 (S544).

[0350]FIG. 33A is a view illustrating a process in which a wireless power
transmitter 100 which is the host searches for a wireless power receiver
200 corresponding to the client.

[0351] Host A being carried out by HostDSP of the power transmission
control unit 112 transmits Cmd_Host_Status to the host physical layer
(S602). The host physical layer responds to host A with
Evt_command_status (S604).

[0352] The host physical layer transmits a device detection message to the
client physical layer being carried out by ClientDPS of the power
receiving control unit 292 (S606). The client physical layer responds to
the host physical layer with resonance shift (S608).

[0354] The client physical layer transmits Cmd_Device_Status to client A
being carried out by ClientDSP of the power receiving control unit 292
(S614). Client A responds to the client physical layer with
Evt_Device_Result (S616). Furthermore, client A responds to the client
physical layer with Cmd_Inquiry_Response (S618).

[0355] The client physical layer transmits a response to the inquiry to
the host physical layer (S620). Furthermore, the client physical layer
transmits Evt_Inquiry_Result to client A (S622).

[0359] Host A transmits Cmd_Host_Status to the host physical layer (S706).
The host physical layer transmits Evt_Command_Status to host A (S708).
The description of the following steps of S710 to S724 is similar to that
of the foregoing steps of S610 to S624 described with reference to FIG.
33A, and thus the detailed description thereof will be omitted.

Third Embodiment

[0360] Hereinafter, a method for ID recognition and collision resolution
between wireless power receivers in wireless power transfer using two-way
communication will be described.

[0361] The wireless power transmitter 100 and wireless power receiver 200
may perform in-band, half-duplex, and two-way communication. In other
words, it may take a process in which the wireless power receiver 200
responds to a request of the wireless power transmitter 100.

[0362] Furthermore, the wireless power transmitter 100 and wireless power
receiver 200 may detect an ID and solve a collision like NFC. It means
that a plurality of wireless power receivers 200 can perform
communication with the wireless power transmitter 100 at the same time
without any collision.

[0363] Furthermore, when detecting a new wireless power receiver 200, the
wireless power transmitter 100 may periodically perform a new ID
detection process.

[0364] Furthermore, when detecting the remaining wireless power receiver
200, the wireless power transmitter 100 may use a request in a time-out
manner.

[0365] Furthermore, in order to detect a rogue wireless power receiver,
the wireless power transmitter 100 monitors all the entire power levels,
and allows the wireless power receiver being obstructed to provide a
correct response (ID information) to be switched to a non-operating state
(or ignored).

[0366] Furthermore, the features of ID recognition and collision
resolution in wireless power transfer are as follows.

[0367] Time slot is formed as short as possible to the maximum to reduce
the possibility of a collision between receivers. Furthermore, when there
occurs a collision between the wireless power receivers 200, the wireless
power transmitter 100 may inform vacant time slot information to the
wireless power receiver 200 using two-way communication and the wireless
power receiver 200 may retry ID detection. According to an embodiment,
the wireless power receiver 200 that has completed ID detection may
perform power transfer.

[0368] When time priority can be checked in a minute manner even in the
time slot, the wireless power transmitter 100 assigns the wireless power
receiver 200 in which a collision has occurred to a vacant time slot to
perform power transfer.

[0369] According to an embodiment disclosed herein, when a collision has
occurred between the wireless power receivers, power transfer can be
immediately implemented without switching the wireless power receiver 200
that has already detected the ID to a sleep mode.

[0370] FIG. 34 is a conceptual view illustrating the phase change of a
wireless power transmitter 100 in the process of the wireless power
transmitter 100 solving a collision between wireless power receivers.

[0371] In the selection state (or phase) (S810), the wireless power
transmitter 100 initializes an ID list. If a new wireless power receiver
200 is detected in the ID detection and collision resolution state
(S820), then the relevant ID, namely, # NEW_ID is added to the list. If a
connection is established through an authentication process or the like
in the configuration and contract state (S830), then it is switched to
the Power transfer state (or phase) (S840). If the number of IDs
contained in the ID list is less than a threshold value (for example, the
number of wireless power receivers that can be charged at a time) in the
Power transfer state (or phase) (S840), then the wireless power
transmitter 100 may perform the operation of the ID detection and
collision resolution state (S820). At this time, the operation of the
Power transfer state (or phase) (S840) can be also maintained.

[0372] On the other hand, when wireless power transfer is terminated and
the wireless power receiver is not detected any more, for example, in the
ID detection and collision resolution state (S820), configuration and
contract state (S830) and Power transfer state (or phase) (S840), the
wireless power transmitter 100 may be switched to the selection state (or
phase) (S810) to initialize the ID list.

[0373]FIG. 35 is a flow chart illustrating a process in which a wireless
power transmitter 100 disclosed herein solves a collision between
wireless power receivers.

[0374] The wireless power transmitter 100 requests an active wireless
power receiver 200 to transmit an ID (S910). Accordingly, if the ID is
transmitted from the wireless power receiver 200, then the wireless power
transmitter 100 collects and checks it, and adds the ID that is not
collided to the list (S920). At this time, the wireless power transmitter
100 waits for the reception of an ID during the preset N time slots.

[0375] The wireless power transmitter 100 determines whether a collision
has occurred between wireless power receivers (S930), and if a collision
has occurred, the wireless power receivers having detected IDs for which
a collision has not occurred are switched to a sleep mode (S940). The
wireless power transmitter 100 returns to the step S910 again to request
an active wireless power receiver 200 to transmit an ID.

[0376] When a collision has not occurred in the step S930, the wireless
power transmitter 100 wakes up all wireless power receivers (S950), and
assigns a time slot to all the identified wireless power receivers
(S960). Subsequently, the wireless power transmitter 100 proceeds to a
configuration and contract state (S970).

[0377]FIG. 36 is a conceptual view illustrating an ID recognition and
collision resolution process of a wireless power transmitter 100
requiring a sleep mode of the wireless power receiver 200.

[0378] The wireless power transmitter 100 can requests an ID to the
wireless power receivers. At this time, the number of time slots can be
set to N.

[0379] The wireless power receiver 200 selects one in a random manner
among time slots from 0 to N-1 in response to a request command of the
wireless power transmitter 100, and transmits an ID to the wireless power
transmitter 100 through the selected time slot. At this time, a collision
has not occurred in time slots 1 and 2, but two wireless power receivers
(rcv1, rcv3) may be collided with each other at time slot 0.

[0380]FIG. 37 is a conceptual view illustrating a quick ID recognition
and collision resolution process of a wireless power transmitter 100
according to an embodiment disclosed herein.

[0381] In a situation that two wireless power receivers (rcv1, rcv3) are
collided with each other at the foregoing time slot 0, the wireless power
receivers (rcv4, rcv2) corresponding to the remaining two time slots in
which a collision has not occurred may immediately perform an
identification and configuration process to receive power in a wireless
manner from the wireless power transmitter 100.

[0382] On the contrary, for the wireless power receivers corresponding to
time slot 0, the wireless power transmitter 100 does not allow a
collision to occur any more through a redistribution process. For
example, the wireless power transmitter 100 assigns one wireless power
receiver (rcv3) among the wireless power receivers (rcv1, rcv3) in which
a collision has occurred to another unoccupied time slot (for example,
time slot 9).

[0383] FIGS. 38A and 38B are other conceptual views illustrating an ID
recognition and collision resolution process of a wireless power
transmitter 100 not requiring a sleep mode of the wireless power receiver
200 according to an embodiment disclosed herein.

[0384] Referring to FIG. 38, in a state that total 10 time slots from 0 to
9 are secured, the wireless power receivers (RCV1, RCV2) may be collided
with each other at time slot 0. At the time slots 1 to 3, each wireless
power receiver (RCV3, RCV4, RCV5) occupies the relevant time slot without
collision. The remaining time slots 4 to 9 are remained as vacant slots
without being occupied by any wireless power receiver.

[0385] On the other hand, the wireless power receivers (RCV3, RCV4, RCV5)
in which a collision has not occurred receive wireless power through a
wireless power signal from the wireless power transmitter 100 through
each time slot.

[0386] Referring to FIG. 38B, the wireless power transmitter 100 detects a
situation that a collision has occurred at time slot 0, and performs a
process of redistributing the wireless power receivers (RCV1, RCV2) in
which a collision has occurred. The wireless power receivers (RCV1, RCV2)
can be redistributed in various ways, and for example, the wireless power
receiver (RCV1) may be assigned to time slot 6, and the wireless power
receiver (RCV2) may be assigned to time slot 7. Then, the wireless power
receiver (RCV1) and wireless power receiver (RCV2) may receive power in a
wireless manner through a wireless power signal from the wireless power
transmitter 100 through the time slots 6 and 7, respectively.

[0387] According to a first embodiment disclosed herein, a wireless power
transmitter may allow a wireless power receiver that has transmitted
identification information in a valid manner to be switched to a sleep
mode, thereby solving a problem that a collision occurs when recognizing
an initial wireless power receiver.

[0388] Furthermore, according to a second embodiment disclosed herein,
when a wireless power transmitter transmits a request message to a
wireless power receiver, the identification information of the relevant
wireless power receiver is also transmitted at the same time, thereby
solving a problem that a collision occurs when recognizing a
single/multiple wireless power receiver(s).

[0389] In addition, according to a third embodiment disclosed herein, a
wireless power transmitter may participate in the time slot assignment of
a wireless power receiver, thereby solving ID recognition and collision
between wireless power receivers.

Patent applications by Dohyeon Son, Seoul KR

Patent applications by Jaesung Lee, Gyeonggi-Do KR

Patent applications by Jeongkyo Seo, Gyeonggi-Do KR

Patent applications by Seonghun Lee, Seoul KR

Patent applications by Yongcheol Park, Gyeonggi-Do KR

Patent applications by LG ELECTRONICS INC.

Patent applications in class TRANSMITTER AND RECEIVER AT SAME STATION (E.G., TRANSCEIVER)

Patent applications in all subclasses TRANSMITTER AND RECEIVER AT SAME STATION (E.G., TRANSCEIVER)